Led tube lamp

ABSTRACT

An LED tube lamp includes a lamp tube, an LED module, a power supply module, a micro switch, and an actuator. The lamp tube has pins for receiving an external driving signal. The power supply module is configured for supplying power to the LED module. The micro switch is coupled to the power supply module. And the actuator is configured to cause the micro switch to change to a closed-circuit position to allow the power supply module to supply power to the LED module for emitting light. When the LED tube lamp is properly installed into a lamp holder, the micro switch closes to electrically connect the power supply module to an external driving signal.

RELATED APPLICATIONS

The present application is a continuation-in-part of U.S. patentapplication Ser. No. 15/055,630, filed Feb. 28, 2016, in the UnitedStates Patent and Trademark Office, the entire contents of which areincorporated herein by reference, and which claims the benefit ofpriority under 35 U.S.C. §119 to the following Chinese PatentApplications, filed with the State Intellectual Property Office (SIPO),the entire contents of each of which are incorporated herein byreference: CN201510104823.3, filed Mar. 10, 2015; CN201510134586.5,filed Mar. 26, 2015; CN201510133689.x, filed Mar. 25, 2015;CN201510173861.4, filed Apr. 14, 2015; CN201510193980.6, filed Apr. 22,2015; CN201510372375.5, filed Jun. 26, 2015; CN201510284720.x, filed May29, 2015; CN201510338027.6, filed Jun. 17, 2015; CN201510315636.x, filedJun. 10, 2015; CN201510406595.5, filed Jul. 10, 2015; CN201510486115.0,filed Aug. 8, 2015; CN201510557717.0, filed Sep. 6, 2015;CN201510595173.7, filed Sep. 18, 2015; CN201510530110.3, filed Aug. 26,2015; CN201510680883.X, filed Oct. 20, 2015; CN201510259151.3, filed May19, 2015; CN201510324394.0, filed Jun. 12, 2015; CN201510373492.3, filedJun. 26, 2015; CN201510482944.1, filed Aug. 7, 2015; CN201510499512.1,filed Aug. 14, 2015; CN201510448220.5, filed Jul. 27, 2015;CN201510483475.5, filed Aug. 8, 2015; CN201510555543.4, filed Sep. 2,2015; CN201510724263.1, filed Oct. 29, 2015; and CN201610050944.9, filedJan. 26, 2016. In addition, this application claims the benefit ofpriority under 35 U.S.C. §119 to the following Chinese PatentApplications: CN201510378322.4, filed Jun. 29, 2015; CN201510428680.1,filed Jul. 20, 2015, and CN201510645134.3, filed Oct. 8, 2015, theentire contents of each of which are incorporated herein by reference.In addition, Chinese Patent Application CN201510075925.7, filed Feb. 12,2015, and Chinese Patent Application CN201510136796.8, filed Mar. 27,2015 are also incorporated by reference herein in their entirety.

TECHNICAL FIELD

The disclosed embodiments relate to LED lighting apparatuses or devices.More particularly, the disclosed embodiments relate to an LED tube lampwith a capability of preventing or reducing the likelihood of anelectronic shock on a user who is installing the LED tube lamp into alamp holder, and its structures.

BACKGROUND

Light emitting diode (LED) lighting technology is rapidly developing toreplace traditional incandescent and fluorescent lighting. LED tubelamps are mercury-free in comparison with fluorescent tube lamps thatneed to be filled with inert gas and mercury. Thus, it is not surprisingthat LED tube lamps are becoming a highly desirable illumination optionamong different available lighting systems used in homes and workplaces,which used to be dominated by traditional lighting options such ascompact fluorescent light bulbs (CFLs) and fluorescent tube lamps.Benefits of LED tube lamps include improved durability and longevity andfar less energy consumption; therefore, when taking into account allfactors, they are typically considered a cost effective lighting option.

Typical LED tube lamps each have a variety of LED lamp components anddriving circuits. The LED lamp components include LED chip-packagingelements, light diffusion elements, high efficient heat dissipatingelements, light reflective boards and light diffusing boards. Heatgenerated by the LED lamp components and the driving elements isconsiderable and mainly dominates the illumination intensity such thatthe heat dissipation should be properly disposed to avoid rapid decreaseof the luminance and the lifetime of the LED lamps. Problems includingpower loss, rapid light decay, and short lifetime due to poor heatdissipation tend to be key factors in consideration of improving theperformance of the LED illuminating system. It is therefore one of theimportant issues to improve on the heat dissipation aspects of the LEDproducts. Nowadays, most LED tube lamps use plastic tubes and metallicelements to dissipate heat from the LEDs. The metallic elements disposedto dissipate heat from the LEDs may be made of aluminum.

Current ways of using LED lamps such as LED tube lamps to replacetraditional lighting devices (referring mainly to fluorescent lamps)include using a ballast-compatible LED tube lamp. Typically on the basisthat there is no need to change the electrical or conductive wirings inthe traditional lamps, an LED tube lamp can be used to directly replacee.g. a fluorescent lamp. But an LED is a nonlinear component withsignificantly different characteristics from a fluorescent lamp.Therefore, using an LED tube lamp with an electronic ballast impacts theresonant circuit design of the electronic ballast, causing acompatibility problem.

Further, the driving of an LED uses a DC driving signal, but the drivingsignal for a fluorescent lamp is a low-frequency, low-voltage AC signalas provided by an AC powerline, a high-frequency, high-voltage AC signalprovided by a ballast, or even a DC signal provided by a battery foremergency lighting applications. Since the voltages and frequencyspectrums of these types of signals differ significantly, simplyperforming a rectification to produce the required DC driving signal inan LED tube lamp is not competent at achieving the LED tube lamp'scompatibility with traditional driving systems of a fluorescent lamp.

In addition, the LED tube lamp may be provided with power via two endsof the lamp and a user can be easily electrically shocked when one endof the lamp is already inserted into a terminal of a power supply whilethe other end is held by the user to reach the other terminal of thepower supply. For example, when the user is not properly installing orhas not properly or completely installed a common LED tube lamp onto alamp holder or socket, the user may be likely to be electrically shockedby an accidental current through the lamp's internal circuitry and thebody of the user touching the lamp or holder. Common or conventional LEDtube lamps do not include a device to prevent the accidental electricalshock on the user who is installing the tube lamp.

As a result, currently applied techniques often fall short whenattempting to address the above-mentioned worse heat conduction, poorheat dissipation, heat deformation, electric shock, weak electricalconnection, smaller driving bandwidth, and variable factor inmanufacture defects.

SUMMARY

Therefore, an object of the disclosure is to provide a significantlyimproved LED tube lamp that dissipates heat more efficiently. A furtherobject of the disclosure is to provide an LED tube lamp that isstructurally stronger. Yet another object of the disclosure is toprovide an LED tube lamp that minimizes the risk of electric shocks.

According to exemplary embodiments, an LED tube lamp includes a lamptube, an LED module, a power supply module, a micro switch, and anactuator. The lamp tube has pins for receiving an external drivingsignal. The LED module is configured for emitting light. The powersupply module is configured for supplying power from the externaldriving signal to the LED module. The micro switch is coupled to thepower supply module. And the actuator is configured to cause the microswitch to change to a closed-circuit position to allow the power supplymodule to supply power to the LED module for emitting light. When theLED tube lamp is properly installed into a lamp holder, the micro switchcloses to electrically connect the power supply module to an externaldriving signal.

According to exemplary embodiments, an LED tube lamp includes a lamptube, an LED lighting module, a power supply module, a safety switch,and an actuator. The lamp tube has pins for receiving an externaldriving signal. The LED lighting module is configured for emittinglight. The power supply module is configured for supplying power fromthe external driving signal to the LED lighting module. The safetyswitch has an input terminal and an output terminal, and includes athyristor, a current-limiting device, and a micro switch. The inputterminal is coupled to one of the first pin and the second pin, and theoutput terminal is to be coupled to the power supply module.

The thyristor is coupled between the input terminal and the outputterminal, and the current-limiting device is coupled between the inputterminal and an end of the micro switch, which has another end coupledto a control terminal of the thyristor. And the actuator is fortriggering/actuating the micro switch to a closed-circuit position toallow the power supply module to supply power to the LED lighting modulefor emitting light. When the LED tube lamp is properly installed into alamp holder, the output terminal of the safety switch is coupled to thepower supply module, and the external driving signal is received, theactuator causes the micro switch to change to the closed-circuitposition to make the thyristor conduct current, which conductingthyristor allows the power supply module to supply power to the LEDlighting module for emitting light.

Various other objects, advantages and features will become readilyapparent from the ensuing detailed description, with certain featuresparticularly pointed out in the appended claims.

BRIEF DESCRIPTION OF FIGURES

The following detailed descriptions, given by way of example, and notintended to be limiting solely thereto, will be best be understood inconjunction with the accompanying figures:

FIG. 1 is a cross-sectional view of an LED tube lamp with a lighttransmissive portion and a reinforcing portion in accordance with anexemplary embodiment;

FIG. 2 is a perspective view illustrating a soldering pad on a bendablecircuit sheet of an LED light strip to be joined together with a printedcircuit board of a power supply, in accordance with an exemplaryembodiment;

FIG. 3 is a planar view illustrating an arrangement of soldering pads ona bendable circuit sheet of an LED light strip in accordance with anexemplary embodiment;

FIG. 4 is a planar view illustrating three soldering pads in a row on abendable circuit sheet of an LED light strip in accordance with anexemplary embodiment;

FIG. 5 is a planar view illustrating soldering pads arranged in two rowson a bendable circuit sheet of an LED light strip in accordance with anexemplary embodiment;

FIG. 6 is a planar view illustrating four soldering pads arranged in arow on a bendable circuit sheet of an LED light strip in accordance withan exemplary embodiment;

FIG. 7 is a planar view illustrating soldering pads arranged in a two bytwo matrix on a bendable circuit sheet of an LED light strip inaccordance with an exemplary embodiment;

FIG. 8 is a planar view illustrating through holes formed on solderingpads in accordance with an exemplary embodiment;

FIG. 9 is a cross-sectional view illustrating a solder bonding process,which utilizes the soldering pads of the bendable circuit sheet of theLED light strip shown in FIG. 8 taken from side view, and a printedcircuit board of a power supply, in accordance with an exemplaryembodiment;

FIG. 10 is a cross-sectional view illustrating a solder bonding process,which utilizes the soldering pads of the bendable circuit sheet of theLED light strip shown in FIG. 8, wherein the through hole of thesoldering pads is near the edge of the bendable circuit sheet, inaccordance with an exemplary embodiment;

FIG. 11 is a planar view illustrating notches formed on soldering padsin accordance with an exemplary embodiment;

FIG. 12 is a cross-sectional view of the LED light strip shown in FIG.11 along the line A-A, according to some embodiments;

FIG. 13A is a block diagram of an exemplary power supply system for anLED tube lamp according to some embodiments;

FIG. 13B is a block diagram of an exemplary LED lamp according to someembodiments;

FIG. 13C is a block diagram of an exemplary power supply system for anLED tube lamp according to some embodiments;

FIG. 13D is a block diagram of an LED lamp according to someembodiments;

FIG. 14A is a schematic diagram of a rectifying circuit according tosome embodiments;

FIG. 14B is a schematic diagram of a rectifying circuit according tosome embodiments;

FIG. 14C is a schematic diagram of a rectifying circuit according tosome embodiments;

FIG. 14D is a schematic diagram of a rectifying circuit according tosome embodiments;

FIG. 15A is a schematic diagram of a terminal adapter circuit accordingto some embodiments;

FIG. 15B is a schematic diagram of a terminal adapter circuit accordingto some embodiments;

FIG. 15C is a schematic diagram of a terminal adapter circuit accordingto some embodiments;

FIG. 15D is a schematic diagram of a terminal adapter circuit accordingto some embodiments;

FIG. 16A is a block diagram of a filtering circuit according to someembodiments;

FIG. 16B is a schematic diagram of a filtering unit according to someembodiments;

FIG. 16C is a schematic diagram of a filtering unit according to someembodiments;

FIG. 16D is a schematic diagram of a filtering unit according to someembodiments;

FIG. 16E is a schematic diagram of a filtering unit according to someembodiments;

FIG. 17A is a schematic diagram of an LED module according to someembodiments;

FIG. 17B is a schematic diagram of an LED module according to someembodiments;

FIG. 17C is a plan view of a circuit layout of an LED module accordingto some embodiments;

FIG. 17D is a plan view of a circuit layout of an LED module accordingto some embodiments;

FIG. 17E is a plan view of a circuit layout of an LED module accordingto some embodiments;

FIG. 18A is a block diagram of an LED lamp according to someembodiments;

FIG. 18B is a block diagram of a driving circuit according to someembodiments;

FIG. 18C is a schematic diagram of a driving circuit according to someembodiments;

FIG. 18D is a schematic diagram of a driving circuit according to someembodiments;

FIG. 18E is a schematic diagram of a driving circuit according to someembodiments;

FIG. 18F is a schematic diagram of a driving circuit according to someembodiments;

FIG. 18G is a block diagram of a driving circuit according to someembodiments;

FIG. 18H is a graph illustrating a relationship between the voltage Vinand the objective current Tout according to certain embodiments;

FIG. 19A is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments;

FIG. 19B is a block diagram of an installation detection moduleaccording to some embodiments;

FIG. 19C is a schematic diagram of a detection pulse generating moduleaccording to some embodiments;

FIG. 19D is a schematic diagram of a detection determining circuitaccording to some embodiments;

FIG. 19E is a schematic diagram of a detection result latching circuitaccording to some embodiments;

FIG. 19F is a schematic diagram of a switch circuit according to someembodiments;

FIG. 20 is a schematic diagram illustrating a structure of an LED tubelamp according to some embodiments; and

FIG. 21 is an alternative micro switch example of FIG. 20, according tosome embodiments.

DETAILED DESCRIPTION

The present disclosure now will be described more fully hereinafter withreference to the accompanying drawings, in which various embodiments areshown. The invention may, however, be embodied in many different formsand should not be construed as limited to the example embodiments setforth herein. These example embodiments are just that—examples—and manyimplementations and variations are possible that do not require thedetails provided herein. It should also be emphasized that thedisclosure provides details of alternative examples, but such listing ofalternatives is not exhaustive. Furthermore, any consistency of detailbetween various examples should not be interpreted as requiring suchdetail—it is impracticable to list every possible variation for everyfeature described herein. The language of the claims should bereferenced in determining the requirements of the invention.

In the drawings, the size and relative sizes of layers and regions maybe exaggerated for clarity. Like numbers refer to like elementsthroughout. Though the different figures show variations of exemplaryembodiments, these figures are not necessarily intended to be mutuallyexclusive from each other. Rather, as will be seen from the context ofthe detailed description below, certain features depicted and describedin different figures can be combined with other features from otherfigures to result in various embodiments, when taking the figures andtheir description as a whole.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items and may beabbreviated as “/”. As used herein, the term “and/or” includes any andall combinations of one or more of the associated listed items. Also,the term “exemplary” is intended to refer to an example or illustration.

Although the figures described herein may be referred to using languagesuch as “one embodiment,” or “certain embodiments,” these figures, andtheir corresponding descriptions are not intended to be mutuallyexclusive from other figures or descriptions, unless the context soindicates. Therefore, certain aspects from certain figures may be thesame as certain features in other figures, and/or certain figures may bedifferent representations or different portions of a particularexemplary embodiment.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers and/or sections, these elements, components, regions, layersand/or sections should not be limited by these terms. Unless the contextindicates otherwise, these terms are only used to distinguish oneelement, component, region, layer or section from another element,component, region, layer or section, for example as a naming convention.Thus, a first element, component, region, layer or section discussedbelow in one section of the specification could be termed a secondelement, component, region, layer or section in another section of thespecification or in the claims without departing from the teachings ofthe present invention. In addition, in certain cases, even if a term isnot described using “first,” “second,” etc., in the specification, itmay still be referred to as “first” or “second” in a claim in order todistinguish different claimed elements from each other.

It will be further understood that the terms “comprises” and/or“comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

It will be understood that when an element is referred to as being“connected” or “coupled” to, or “on” another element, it can be directlyconnected or coupled to, or on the other element or intervening elementsmay be present. In contrast, when an element is referred to as being“directly connected,” “directly coupled,” or “directly on” anotherelement, there are no intervening elements present. Other words used todescribe the relationship between elements should be interpreted in alike fashion (e.g., “between” versus “directly between,” “adjacent”versus “directly adjacent,” etc.). However, the term “contact,” as usedherein refers to direct connection (i.e., touching) unless the contextindicates otherwise.

Embodiments described herein will be described referring to plan viewsand/or cross-sectional views by way of ideal schematic views.Accordingly, the exemplary views may be modified depending onmanufacturing technologies and/or tolerances. Therefore, the disclosedembodiments are not limited to those shown in the views, but includemodifications in configuration formed on the basis of manufacturingprocesses. Therefore, regions exemplified in figures may have schematicproperties, and shapes of regions shown in figures may exemplifyspecific shapes of regions of elements to which aspects of the inventionare not limited.

Although corresponding plan views and/or perspective views of somecross-sectional view(s) may not be shown, the cross-sectional view(s) ofdevice structures illustrated herein provide support for a plurality ofdevice structures that extend along two different directions as would beillustrated in a plan view, and/or in three different directions aswould be illustrated in a perspective view. The two different directionsmay or may not be orthogonal to each other. The three differentdirections may include a third direction that may be orthogonal to thetwo different directions. The plurality of device structures may beintegrated in a same electronic device. For example, when a devicestructure (e.g., a solder structure or a pad structure) is illustratedin a cross-sectional view, an electronic device may include a pluralityof the device structures (e.g., solder structures or pad structures), aswould be illustrated by a plan view of the electronic device. Theplurality of device structures may be arranged in an array and/or in atwo-dimensional pattern.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element's or feature's relationship to another element(s)or feature(s) as illustrated in the figures. It will be understood thatthe spatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

Terms such as “same,” “planar,” or “coplanar,” as used herein whenreferring to orientation, layout, location, shapes, sizes, amounts, orother measures do not necessarily mean an exactly identical orientation,layout, location, shape, size, amount, or other measure, but areintended to encompass nearly identical orientation, layout, location,shapes, sizes, amounts, or other measures within acceptable variationsthat may occur, for example, due to manufacturing processes. The term“substantially” may be used herein to emphasize this meaning, unless thecontext or other statements indicate otherwise. For example, itemsdescribed as “substantially the same,” “substantially equal,” or“substantially planar,” may be exactly the same, equal, or planar, ormay be the same, equal, or planar within acceptable variations that mayoccur, for example, due to manufacturing processes.

Terms such as “about” or “approximately” may reflect amounts, sizes,orientations, or layouts that vary only in a small relative manner,and/or in a way that does not significantly alter the operation,functionality, or structure of certain elements. For example, a rangefrom “about 0.1 to about 1” may encompass a range such as a 0%-5%deviation around 0.1 and a 0% to 5% deviation around 1, especially ifsuch deviation maintains the same effect as the listed range.

As used herein, items described as being “electrically connected” areconfigured such that an electrical signal can be passed from one item tothe other. Therefore, a passive electrically conductive component (e.g.,a wire, pad, internal electrical line, etc.) physically connected to apassive electrically insulative component (e.g., a prepreg layer of aprinted circuit board, an electrically insulative adhesive connectingtwo device, an electrically insulative underfill or mold layer, etc.) isnot electrically connected to that component. Moreover, items that are“directly electrically connected,” to each other are electricallyconnected through one or more passive elements, such as, for example,wires, pads, internal electrical lines, through vias, etc. As such,directly electrically connected components do not include componentselectrically connected through active elements, such as transistors ordiodes. Directly electrically connected elements may be directlyphysically connected and directly electrically connected.

Components described as thermally connected or in thermal communicationare arranged such that heat will follow a path between the components toallow the heat to transfer from the first component to the secondcomponent. Simply because two components are part of the same device orpackage does not make them thermally connected. In general, componentswhich are heat-conductive and directly connected to otherheat-conductive or heat-generating components (or connected to thosecomponents through intermediate heat-conductive components or in suchclose proximity as to permit a substantial transfer of heat) will bedescribed as thermally connected to those components, or in thermalcommunication with those components. On the contrary, two componentswith heat-insulative materials therebetween, which materialssignificantly prevent heat transfer between the two components, or onlyallow for incidental heat transfer, are not described as thermallyconnected or in thermal communication with each other. The terms“heat-conductive” or “thermally-conductive” do not apply to a particularmaterial simply because it provides incidental heat conduction, but areintended to refer to materials that are typically known as good heatconductors or known to have utility for transferring heat, or componentshaving similar heat conducting properties as those materials.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and/orthe present application, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein. In addition,unless the context indicates otherwise, steps described in a particularorder need not occur in that order.

Referring to FIG. 1, in accordance with an exemplary embodiment, an LEDtube lamp comprises a lamp tube 1 and an LED light assembly. The lamptube 1 includes a light transmissive portion 105 and a reinforcingportion 107. The reinforcing portion 107 is fixedly connected to thelight transmissive portion 105.

The LED light assembly is disposed inside the lamp tube 1 and includesan LED light source 202 and an LED light strip 2. The LED light sourceis thermally and electrically connected to the LED light strip 2, whichis in turn thermally connected to the reinforcing portion 107. Thoughonly one LED light source 202 is shown, a plurality of light sources 202may be arranged on the LED light strip 2. For example, light sources 202may be arranged in one or more rows extending along a length directionof the LED light strip 2, which may extend along a length direction ofthe lamp tube 1. Heat generated by the LED light source 202 is firsttransmitted to the LED light strip 2 and then to the reinforcing portion107 before egressing the lamp tube 1. Thermal connection is achievedwith thermally conductive tapes or conventional mechanical fastenerssuch as screws aided by thermal grease to eliminate air gaps frominterface areas. In certain embodiments, the LED light strip 2 may beformed from a bendable circuit sheet, for example that may be flexible.As described further below, the bendable circuit sheet, also describedas a bendable circuit board, may be disposed on the lamp tube 1 to bebent away from the lamp tube 1, for example at longitudinal ends of thebendable circuit sheet.

Typically, the lamp tube 1 has a shape of an elongated cylinder, whichis a straight structure. However, the lamp tube 1 can take any curvedstructure such as a ring or a horseshoe. The cross section of the lamptube 1 is typically a circle, but may also be other shapes, such as anellipse or a polygon. Alternatively, the cross section of the lamp tube1 may have an irregular shape depending on the shapes of, respectively,the light transmissive portion 105 and the reinforcing portion 107 andon the manner the two portions interconnect to form the lamp tube 1.

The lamp tube 1 is a glass tube, a plastic tube or a tube made of anyother suitable material or combination of materials. In someembodiments, a plastic lamp tube is made from light transmissiveplastic, thermally conductive plastic or a combination of both. Forexample, the light transmissive plastic may be one of translucentpolymer matrices such as polymethyl methacrylate, polycarbonate,polystyrene, poly(styrene-co-methyl methacrylate) and a mixture thereof.In some embodiments, the strength and elasticity of thermally conductiveplastic is enhanced by bonding a plastic matrix with glass fibers. In anembodiment, an outer shell of lamp tube includes a plurality of layersmade from distinct materials. For example, the lamp tube may include aplastic tube coaxially sheathed by a glass tube.

In one embodiment, the light transmissive portion 105 is made from lighttransmissive plastic, and the reinforcing portion is 107 made fromthermally conductive plastic. Injection molding may be used forproducing the light transmissive portion 105 in a first piece and forproducing the reinforcing portion 107 in a separate second piece. Thefirst piece and the second piece may be configured to be clippedtogether, buckled together, glued together or otherwise fixedlyinterconnected to form the lamp tube 1. Alternatively, injection moldingmay be used for producing the entire lamp tube 1, which includes thelight transmissive portion 105 and the reinforcing portion 107, in anintegral piece of the lamp tube 1, by feeding two types of plasticmaterials into a molding process. In an alternative embodiment, thereinforcing portion is made of metal having good thermal conductivitysuch as aluminum alloy and copper alloy.

Respective shapes of the light transmissive portion 105 and thereinforcing portion 107, how the two portions 105, 107 interconnect toform the lamp tube 1 and, particularly, the respective proportions ofthe two portions 105, 107 in the lamp tube depend on a desired totalityof considerations such as field angle, heat dissipation efficiency andstructural strength. A wider field angle—potentially at the expense ofheat dissipation capability and structural strength—is achieved when theproportion of the light transmissive portion increases 105 in relationto that of the reinforcing portion 107. By contrast, the lamp tubebenefits from an increased proportion of the reinforcing portion 107 inrelation to that of the light transmissive portion in such ways asbetter heat dissipation and rigidity but potentially loses field angle.

In some embodiments, the reinforcing portion 107 includes a plurality ofprotruding parts. In other embodiments, a plurality of protruding partsare disposed on the surface of the LED light strip 2 that is not coveredby the LED light assembly. Like fins on a heatsink, each protruding partboosts heat dissipation by increasing the surface area of thereinforcing portion 107 and the LED light strip 2. The protruding partsare disposed equidistantly, or alternatively, not equidistantly.

Referring to FIG. 1, the lamp tube 1 depicted in FIG. 1 has a shape of acircular cylinder. For example, a cross section of the lamp tube 1defines a circle. A line H-H cuts the circle horizontally into two equalhalves along a diameter of the circle. A cross section of the lighttransmissive portion 105 defines an upper segment on the circle. A crosssection of the reinforcing portion 107 defines a lower segment on thecircle. A dividing line 104 parallel to the line H-H is shared by thetwo segments. In the embodiment, the dividing line 104 sits exactly onthe line H-H. Consequently, the area of the upper segment is the same asthat of the lower segment. In one embodiment, the cross section of thelight transmissive portion 105 has a same area as that of thereinforcing portion 107.

In an alternative embodiment, the dividing line 104 is spaced apart fromthe line H-H. For example, when the dividing line 104 is below the lineH-H, the upper segment, which encompasses the light transmissiveportion, has a greater area than the lower segment, which encompassesthe reinforcing portion. The lamp tube, which includes an enlarged lighttransmissive portion, is thus configured to achieve a field angle widerthan 180 degrees; however, other things equal, the lamp tube surrenderssome heat dissipation capability, structural strength or both due to adiminished reinforcing portion 107. By contrast, the lamp tube 1 mayhave an enlarged reinforcing portion 107 and a diminished lighttransmissive portion 105 if the dividing line rises above the line H-H.Other things equal, the lamp tube 1, now having an enlarged reinforcingportion 107, is configured to exhibit higher heat dissipationcapability, structural strength or both; however, the field angle of thelamp tube 1 will dwindle due to diminished dimensions of the lighttransmissive portion 105. In either case, the dividing line 104 may beparallel to the line H-H, or where the areas of the upper segment andlower segment are not equal, in some embodiments, rather than beingparallel, the dividing line 104 may have another orientation. Forexample, each dividing line 104 may extend in a direction that extendsradially from a center of the lamp tube 1, as viewed from across-section.

According to certain embodiments, the LED tube lamp is configured toconvert bright spots coming from the LED light source into an evenlydistributed luminous output. In one embodiment, a light diffusion layeris disposed on an inner surface of the lamp tube 1 or an outer surfaceof the lamp tube 1. In another embodiment, a diffusion laminate isdisposed over the LED light source 202. In yet another embodiment, thelamp tube 1 has a glossy outer surface and a frosted inner surface. Theinner surface is rougher than the outer surface. The roughness R_(a) ofthe inner surface may be, for example, from 0.1 to 40 μm. In someembodiments, roughness R_(a) of the inner surface may be from 1 to 20μm. Controlled roughness of the surface is obtained mechanically, forexample, by a cutter grinding against a workpiece, deformation on asurface of a workpiece being cut off or high frequency vibration in themanufacturing system. Alternatively, roughness is obtained chemically,for example, by etching a surface. Depending on the luminous effect thelamp tube 1 is designed to produce, a suitable combination of amplitudeand frequency of a roughened surface is provided by a matchingcombination of workpiece and finishing technique. Also, various of thediffusion mechanisms described herein can be combined in various ways toobtain a desired effect.

In alternative embodiments, the diffusion layer is in the form of anoptical diffusion coating, which is composed of any one of calciumcarbonate, halogen calcium phosphate and aluminum oxide, or anycombination thereof. When the optical diffusion coating is made from acalcium carbonate with suitable solution, an excellent light diffusioneffect and transmittance to exceed 90% can be obtained.

In the embodiment, the composition of the diffusion layer in form of theoptical diffusion coating includes calcium carbonate, strontiumphosphate (e.g., CMS-5000, white powder), thickener, and a ceramicactivated carbon (e.g., ceramic activated carbon SW-C, which is acolorless liquid). Specifically, in some embodiments, such an opticaldiffusion coating on the inner circumferential surface of the glass tubehas an average thickness ranging between about 20 to about 30 μm. Forexample, the thickness, which may be a uniform thickness, may be 20 μm,30 μm, or may have a value therebetween. A light transmittance of thediffusion layer using this optical diffusion coating is about 90%.Generally speaking, the light transmittance of the diffusion layerranges from 85% to 96%. For example, the light transmittance of thediffusion layer may be 85%, 96%, or have a value therebetween. Inaddition, this diffusion layer can also provide electrical isolation forreducing risk of electric shock to a user upon breakage of the lamp tube1. Furthermore, the diffusion layer provides an improved illuminationdistribution uniformity of the light outputted by the LED light sources202 such that the light can illuminate the back of the light sources 202and the side edges of the bendable circuit sheet so as to avoid theformation of dark regions inside the lamp tube 1 and improve theillumination comfort. In another possible embodiment, the lighttransmittance of the diffusion layer can be reduced to be about 92% to94% while the thickness of the diffusion layer ranges from about 200 toabout 300 μm.

In another embodiment, the optical diffusion coating can also be made ofa mixture including a calcium carbonate-based substance, some reflectivesubstances like strontium phosphate or barium sulfate, a thickeningagent, ceramic activated carbon, and deionized water. The mixture iscoated on the inner circumferential surface of the glass tube and has anaverage thickness ranging between about 20 to about 30 μm. In view ofthe diffusion phenomena in microscopic terms, light is reflected byparticles. The particle size of the reflective substance such asstrontium phosphate or barium sulfate will be much larger than theparticle size of the calcium carbonate. Therefore, adding a small amountof reflective substance in the optical diffusion coating can effectivelyincrease the diffusion effect of light.

In other embodiments, halogen calcium phosphate or aluminum oxide canalso serve as the main material for forming the diffusion layer. Theparticle size of the calcium carbonate is about 2 to 4 while theparticle size of the halogen calcium phosphate and aluminum oxide areabout 4 to 6 μm and 1 to 2 μm, respectively. When the lighttransmittance is required to be 85% to 92%, the average thickness forthe optical diffusion coating mainly having the calcium carbonate may beabout 20 to about 30 while the average thickness for the opticaldiffusion coating mainly having the halogen calcium phosphate may beabout 25 to about 35 and the average thickness for the optical diffusioncoating mainly having the aluminum oxide may be about 10 to about 15However, when the required light transmittance is up to 92% and evenhigher, the optical diffusion coating mainly having the calciumcarbonate, the halogen calcium phosphate, or the aluminum oxide can bemade thinner.

The main material and the corresponding thickness of the opticaldiffusion coating can be decided according to the place for which thelamp tube 1 is used and the light transmittance required. In someembodiments, the higher the desired light transmittance of the diffusionlayer, the more apparent the grainy visual appearance of the lightsources is.

In one embodiment, the LED tube lamp is configured to reduce internalreflectance by applying a layer of anti-reflection coating to an innersurface of the lamp tube 1. The coating has an upper boundary, whichdivides the inner surface of the lamp tube and the anti-reflectioncoating, and a lower boundary, which divides the anti-reflection coatingand the air in the lamp tube 1. Light waves reflected by the upper andlower boundaries of the coating interfere with one another to reducereflectance. In certain embodiments, the coating is made from a materialwith a refractive index of a square root of the refractive index of thelight transmissive portion 105 of the lamp tube 1 by vacuum deposition.Tolerance of the coating's refractive index is ±20%. The thickness ofthe coating is chosen to produce destructive interference in the lightreflected from the interfaces and constructive interference in thecorresponding transmitted light. In an additional embodiment,reflectance is further reduced by using alternating layers of alow-index coating and a higher-index coating. The multi-layer structureis designed to, when setting parameters such as combination andpermutation of layers, thickness of a layer, refractive index of thematerial, give low reflectivity over a broad band that covers at least60%, or in some embodiments, 80% of the wavelength range beaming fromthe LED light source 202. In some embodiments, three successive layersof anti-reflection coatings are applied to an inner surface of the lamptube 1 to obtain low reflectivity over a wide range of frequencies. Thethicknesses of the coatings are chosen to give the coatings opticaldepths of, respectively, one half, one quarter and one half of thewavelength range coming from the LED light source 202. Dimensionaltolerance for the thickness of the coating is set at ±20%.

In some embodiments, any type of power supply can be electricallyconnected to the LED light strip 2 by means of a traditional wirebonding technique, in which a metal wire has an end connected to thepower supply and has the other end connected to the LED light strip 2.Furthermore, the metal wire may be wrapped with an electricallyinsulating tube to protect a user from being electrically shocked.However, the bonded wires tend to be easily broken during transportationand can therefore cause quality issues.

In still another embodiment, the connection between the power supply 5and the LED light strip 2 may be accomplished via soldering (e.g., usingtin), rivet bonding, or welding. One way to secure the LED light strip 2is to provide the adhesive sheet at one side thereof and adhere the LEDlight strip 2 to the inner surface of the lamp tube 1 via the adhesivesheet. Two ends of the LED light strip 2 can be either fixed to ordetached from the inner surface of the lamp tube 1.

In case where two ends of the LED light strip 2 are fixed to the innersurface of the lamp tube 1, a bendable circuit sheet of the LED lightstrip 2 may be provided with a female plug, and a power supply, forexample at ends of the bendable circuit sheet, is provided with the maleplug to accomplish the connection between the LED light strip 2 and thepower supply. In this case, the male plug of the power supply isinserted into the female plug to establish electrical connection.

In a case where two ends of the LED light strip 2 are detached from theinner surface of the lamp tube (e.g., if an adhesive wears out) and thatthe LED light strip 2 is connected to the power supply via wire-bonding,any movement in subsequent transportation is likely to cause the bondedwires to break. Therefore, in some embodiments, the connection betweenthe light strip 2 and a power supply at ends of the light strip 2 couldbe accomplished via direct soldering. For example, the ends of the LEDlight strip 2 including a bendable circuit sheet can be arranged to passover a strengthened transition region of a lamp tube, and be directlysolder bonded to an output terminal of a power supply such that theproduct quality is improved without using wires. In this way, the femaleplug and the male plug respectively provided for the LED light strip 2and the power supply are no longer needed. As discussed herein, atransition region of the lamp tube refers to regions outside a centralportion of the lamp tube and inside terminal ends of the lamp tube. Forexample, a central portion of the lamp tube may have a constantdiameter, and each transition region between the central portion and aterminal end of the lamp tube may have a changing diameter (e.g., atleast part of the transition region may become more narrow moving in adirection from the central portion to the terminal end of the lamptube). End caps including the power supply may be disposed at theterminal ends of the lamp tube, and may cover part of the transitionregion. In some embodiments, the ends of the bendable circuit sheet maybe connected to a power supply in an end cap of the LED tube lamp. Forexample, the ends may be connected in a manner such that a portion ofthe bendable circuit sheet is bent away from the lamp tube and passesthrough the transition region where a lamp tube narrows, and such thatthe bendable circuit sheet vertically overlaps part of a power supplywithin an end cap of the LED tube lamp.

Referring to FIG. 2, a power supply 5 described herein may includevarious elements for providing power to the LED light strip 2. Forexample, it may include power converters or other circuit elements forproviding power to the LED light strip 2. In some embodiments, powersupply 5 may include a printed circuit board. An output terminal of theprinted circuit board of the power supply 5 may have soldering pads “a”provided with an amount of solder (e.g., tin solder) with a thicknesssufficient to later form a solder joint. Correspondingly, the ends ofthe LED light strip 2 may have soldering pads “b”. The soldering pads“a” on the output terminal of the printed circuit board of the powersupply 5 are soldered to the soldering pads “b” on the LED light strip 2via the solder on the soldering pads “a”. The soldering pads “a” and thesoldering pads “b” may be face to face during soldering such that theconnection between the LED light strip 2 and the printed circuit boardof the power supply 5 is the most firm. However, this kind of solderingmay involve a thermo-compression head pressing on the rear surface ofthe LED light strip 2 and heating the solder, e.g., the LED light strip2 intervenes between the thermo-compression head and the solder. Thismay cause reliability problems. Referring to FIG. 8, a through hole maybe formed in each of the soldering pads “b” on the LED light strip 2 toallow the soldering pads “b” to overlay the soldering pads “b” withoutbeing face-to-face. In this case, the thermo-compression head directlypresses solder on the soldering pads “a” on surface of the printedcircuit board of the power supply 5 when the soldering pads “a” and thesoldering pads “b” are vertically aligned.

Referring again to FIG. 2, two ends of the LED light strip 2 detachedfrom the inner surface of the lamp tube 1 are formed as freely extendingportions 21, while most of the LED light strip 2 is attached and securedto the inner surface of the lamp tube 1. One of the freely extendingportions 21 has the soldering pads “b” as mentioned above. Uponassembling of the LED tube lamp, the freely extending end portions 21along with the soldered connection of the printed circuit board of thepower supply 5 and the LED light strip 2 would be coiled, curled up ordeformed to be fittingly accommodated inside the lamp tube 1. The freelyextending portions 21 may be different from a fixed portion of the LEDlight strip 2 attached to the lamp tube 1, in that the fixed portion mayconform to the shape of the inner surface of the lamp tube 1 and may befixed thereto, while the freely extending portion 21 may have a shapethat does not conform to the shape of the lamp tube 1. As shown in FIG.2, the freely extending portion 21 may be bent away from the lamp tube1. For example, there may be a space between an inner surface of thelamp tube 1 and the freely extending portion 21.

In one embodiment, during the connection of the LED light strip 2 andthe power supply 5, the soldering pads “b” and the soldering pads “a”and the LED light sources 202 are on surfaces facing toward the samedirection and the soldering pads “b” on the LED light strip 2 are eachformed with a through hole “e” as shown in FIG. 8 such that thesoldering pads “b” and the soldering pads “a” communicate with eachother via the through holes “e”. When the freely extending end portions21 are deformed due to contraction or curling up, the solderedconnection of the printed circuit board of the power supply 5 and theLED light strip 2 exerts a lateral tension on the power supply 5.Furthermore, the soldered connection of the printed circuit board of thepower supply 5 and the LED light strip 2 also exerts a downward tensionon the power supply 5 when compared with the situation where thesoldering pads “a” of the power supply 5 and the soldering pads “b” ofthe LED light strip 2 are face to face. This downward tension on thepower supply 5 comes from the solders (e.g., tin solders) inside thethrough holes “e” and forms a stronger and more secure electricalconnection between the LED light strip 2 and the power supply 5.

Referring to FIG. 3, in one embodiment, the soldering pads “b” of theLED light strip 2 are two separate pads to electrically connect thepositive and negative electrodes of the bendable circuit sheet of theLED light strip 2, respectively. The size of the soldering pads “b” maybe, for example, about 3.5×2 mm². The printed circuit board of the powersupply 5 is correspondingly provided with soldering pads “a” havingreserved tin solders (or solders formed from other suitable metal) andthe height of the tin solders suitable for subsequent automatic solderbonding process may be generally, for example, about 0.1 to 0.7 mm, insome embodiments 0.3 to 0.5 mm. In some exemplary embodiments, theheight of the tin solders suitable for a subsequent automatic solderbonding process may be about 0.4 mm. An electrically insulating throughhole “c” may be formed between the two soldering pads “b” to isolate andprevent the two soldering pads from electrically shorting duringsoldering. Furthermore, an extra positioning opening “d” may also beprovided behind the electrically insulating through hole “c” to allow anautomatic soldering machine to quickly recognize the position of thesoldering pads “b”.

There is at least one soldering pad “b” for separately connecting to thepositive and negative electrodes of the LED light sources 202. For thesake of achieving scalability and compatibility, the amount of thesoldering pads “b” on each end of the LED light strip 2 may be more thanone such as two, three, four, or more than four. When there is only onesoldering pad “b” provided at each end of the LED light strip 2, the twoends of the LED light strip 2 are electrically connected to the powersupply 5 to form a loop, and various electrical components can be used.For example, a capacitance may be replaced by an inductance to performcurrent regulation. Referring to FIGS. 4 to 7, when each end of the LEDlight strip 2 has three soldering pads, the third soldering pad can begrounded; when each end of the LED light strip 2 has four solderingpads, the fourth soldering pad can be used as a signal input terminal.Correspondingly, in various embodiments, the power supply 5 should havesame amount of soldering pads “a” as that of the soldering pads “b” onthe LED light strip 2. As long as electrical short between the solderingpads “b” can be prevented, the soldering pads “b” can be arrangedaccording to the dimension of the actual area for disposition, forexample, three soldering pads can be arranged in a row or two rows. Inother embodiments, the amount of the soldering pads “b” on the bendablecircuit sheet of the LED light strip 2 may be reduced by rearranging thecircuits on the bendable circuit sheet of the LED light strip 2. Thelesser the amount of the soldering pads, the easier the fabricationprocess becomes. On the other hand, a greater number of soldering padsmay improve and secure the electrical connection between the LED lightstrip 2 and the output terminal of the power supply 5.

Referring to FIG. 8, as discussed previously, in another embodiment,each soldering pads “b” is formed with a through hole “e” having adiameter generally of about 1 to 2 mm, in some embodiments of about 1.2to 1.8 mm, and in yet some embodiments of about 1.5 mm. The through hole“e” connects the soldering pad “a” with the soldering pad “b” so thatthe solder on the soldering pads “a” passes through the through holes“e” and finally reaches the soldering pads “b”. A smaller through holewould make it difficult for the solder to pass. The solder accumulatesaround the through holes “e” upon exiting the through holes “e” andcondenses to form a solder ball “g” with a larger diameter than that ofthe through holes “e” upon condensing. Such a solder ball “g” functionsas a rivet to further increase the stability of the electricalconnection between the soldering pads “a” on the power supply 5 and thesoldering pads “b” on the LED light strip 2.

Referring to FIGS. 9 to 10, in other embodiments, when a distance fromthe through hole “e” to the side edge of the LED light strip 2 is lessthan 1 mm, the tin solder may pass through the through hole “e” toaccumulate on the periphery of the through hole “e”, and extra tinsolder may spill over the soldering pads “b” to reflow along the sideedge of the LED light strip 2 and join the tin solder on the solderingpads “a” of the power supply 5. The tin solder then condenses to form astructure like a rivet to firmly secure the LED light strip 2 onto theprinted circuit board of the power supply 5 such that reliable electricconnection is achieved. Referring to FIG. 11 and FIG. 12, in anotherembodiment, the through hole “e” can be replaced by a notch “f” formedat the side edge of the soldering pads “b” for the tin solder to easilypass through the notch “f” and accumulate on the periphery of the notch“f” and to form a solder ball with a larger diameter than that of thenotch “e” upon condensing. Such a solder ball may be formed like aC-shape rivet to enhance the secure capability of the electricallyconnecting structure.

The abovementioned through hole “e” or notch “f” might be formed inadvance of soldering or formed by direct punching with athermo-compression head during soldering. The portion of thethermo-compression head for touching the tin solder may be flat,concave, or convex, or any combination thereof. The portion of thethermo-compression head for restraining the object to be soldered suchas the LED light strip 2 may be strip-like or grid-like. In someembodiments, the portion of the thermo-compression head for touching thetin solder does not completely cover the through hole “e” or the notch“f,” to make sure that the tin solder is able to pass through thethrough hole “e” or the notch “f”. The portion of the thermo-compressionhead being concave may function as a compartment to receive the solderball.

The power supply 5 is electrically coupled to the LED light strip 2 andvarious features and applications of the related power supply assemblyare described below. The example circuits and the assemblies mentionedbelow may be all disposed on the reinforcing portion in the lamp tube toincrease the heat dissipating area and efficiency, simplify the circuitdesign in the end cap, and provide an easier control for the length ofthe lamp tube in manufacturing. However, in some embodiments, some ofexample circuits and assemblies described below are kept in the end cap(e.g. resistors, or capacitors, or the components with smaller volume orsmaller power consumption, the components generating less heat or havingbetter heat resistance) and the others are disposed on the reinforcingportion (e.g. chips, inductors, transistors, or the components withbigger volume, the components generating much heat or having poor heatresistance) so as to increase the heat dissipating area and efficiencyand simplify the circuit design in the end cap. The implementations arenot limited to the disclosed embodiments.

In some embodiments, for example, the circuits and the assembliesdisposed on the reinforcing portion in the lamp tube may be implementedby surface mount components. Some of the circuits and the assemblies maybe disposed on the LED light strip and then be electrically connected tothe circuit(s) kept in the end cap via a male-female plug or a wire withan insulating coating/layer for achieving the isolation effect. Or, thecircuits and the assemblies related to the power supply may all bedisposed on the LED light strip to reduce the reserved length of the LEDlight strip, which is used for connecting to other circuit board(s), andalso to reduce the allowable error length and omit the process forelectrically connecting two or more circuit boards (e.g., the bendablecircuit board and a circuit board of a power supply), so that thelengths of the lamp tube and the LED light strip could be controlledmore precisely. The circuits and the assemblies and the LEDs may bedisposed on the same or different side of the reinforcing portion. Insome embodiments, the circuits and the assemblies and the LEDs may bedisposed on the same side to reduce the process of making throughhole(s) on the reinforcing portion for electrically connection. Theimplementations are not limited to the disclosed embodiments.

Next, examples of the circuit design and of a power supply system andmodule are described as follows.

FIG. 13A is a block diagram of a power supply system for an LED tubelamp according to an embodiment. Referring to FIG. 13A, an AC powersupply 508 is used to supply an AC supply signal, and may be an ACpowerline with a voltage rating, for example, in 100-277 volts and afrequency rating, for example, of 50 or 60 Hz. A lamp driving circuit505 receives and then converts the AC supply signal into an AC drivingsignal as an external driving signal. In some embodiments, the powersupply 508 and the lamp driving circuit 505 are outside of the LED tubelamp. For example, the lamp driving circuit 505 may be part of a lampsocket or lamp holder into which the LED tube lamp is inserted. Lampdriving circuit 505 may be for example an electronic ballast used toconvert the AC powerline into a high-frequency high-voltage AC drivingsignal. Common types of electronic ballast include instant-startballast, program-start or rapid-start ballast, etc., which may all beapplicable to the LED tube lamp. The voltage of the AC driving signal islikely higher than 300 volts, and is in some embodiments in the range ofabout 400-700 volts. The frequency of the AC driving signal may behigher than 10 k Hz. In some embodiments, the frequency of the ACdriving signal may be in the range of about 20 k-50 k Hz. The LED tubelamp 500 receives an external driving signal and is thus driven to emitlight. In one embodiment, the external driving signal comprises the ACdriving signal from lamp driving circuit 505. In one embodiment, LEDtube lamp 500 is in a driving environment in which it is power-suppliedat its one end cap having two conductive pins 501 and 502, which arecoupled to lamp driving circuit 505 to receive the AC driving signal.The two conductive pins 501 and 502 may be electrically connected to,either directly or indirectly, the lamp driving circuit 505.

It is worth noting that lamp driving circuit 505 may be omitted and istherefore depicted by a dotted line. In one embodiment, if lamp drivingcircuit 505 is omitted, AC power supply 508 is directly connected topins 501 and 502, which then receive the AC supply signal as an externaldriving signal.

In addition to the above use with a single-end power supply, LED tubelamp 500 may instead be used with a dual-end power supply to one pin ateach of the two ends of an LED lamp tube.

FIG. 13B is a block diagram of an LED lamp according to one embodiment.Referring to FIG. 13B, a power supply module of the LED lamp includes arectifying circuit 510 and a filtering circuit 520, and may also includesome components of an LED lighting module 530. Rectifying circuit 510 iscoupled to pins 501 and 502 to receive and then rectify an externaldriving signal, so as to output a rectified signal at output terminals511 and 512. The external driving signal may be the AC driving signal orthe AC supply signal described with reference to FIG. 13A, or may evenbe a DC signal, which embodiments do not alter the LED lamp. Filteringcircuit 520 is coupled to the first rectifying circuit for filtering therectified signal to produce a filtered signal. For instance, filteringcircuit 520 is coupled to terminals 511 and 512 to receive and thenfilter the rectified signal, so as to output a filtered signal at outputterminals 521 and 522. LED lighting module 530 is coupled to filteringcircuit 520, to receive the filtered signal for emitting light. Forinstance, LED lighting module 530 may be a circuit coupled to terminals521 and 522 to receive the filtered signal and thereby to drive an LEDunit (not shown) in LED lighting module 530 to emit light. Details ofthese operations are described in below descriptions of certainembodiments.

Although two output terminals 511 and 512 and two output terminals 521and 522 are depicted in embodiments of these Figs., in practice thenumber of ports or terminals for coupling between rectifying circuit510, filtering circuit 520, and LED lighting module 530 may be one ormore depending on the signal transmission between the circuits ordevices.

In addition, the power supply module of the LED lamp described in FIG.13B, and embodiments of the power supply module of an LED lamp describedbelow, may each be used in the LED tube lamp 500 in FIG. 13A, and mayalso be used in any other type of LED lighting structure having twoconductive pins used to conduct power, such as LED light bulbs, personalarea lights (PAL), plug-in LED lamps with different types of bases (suchas types of PL-S, PL-D, PL-T, PL-L, etc.), etc.

FIG. 13C is a block diagram of a power supply system for an LED tubelamp according to an embodiment. Referring to FIG. 13C, an AC powersupply 508 is used to supply an AC supply signal. A lamp driving circuit505 receives and then converts the AC supply signal into an AC drivingsignal. An LED tube lamp 500 receives an AC driving signal from lampdriving circuit 505 and is thus driven to emit light. In thisembodiment, LED tube lamp 500 is power-supplied at its both end capsrespectively having two pins 501 and 502 and two pins 503 and 504, whichare coupled to lamp driving circuit 505 to concurrently receive the ACdriving signal to drive an LED unit (not shown) in LED tube lamp 500 toemit light. AC power supply 508 may be e.g. the AC powerline, and lampdriving circuit 505 may be a stabilizer or an electronic ballast.

FIG. 13D is a block diagram of an LED lamp according to an embodiment.Referring to FIG. 13D, a power supply module of an LED lamp includes arectifying circuit 510, a filtering circuit 520, and a rectifyingcircuit 540, and may also include some components of an LED lightingmodule 530. Rectifying circuit 510 is coupled to pins 501 and 502 toreceive and then rectify an external driving signal conducted by pins501 and 502. Rectifying circuit 540 is coupled to pins 503 and 504 toreceive and then rectify an external driving signal conducted by pins503 and 504. Therefore, the power supply module of the LED lamp mayinclude two rectifying circuits 510 and 540 configured to output arectified signal at output terminals 511 and 512. Filtering circuit 520is coupled to terminals 511 and 512 to receive and then filter therectified signal, so as to output a filtered signal at output terminals521 and 522. LED lighting module 530 is coupled to terminals 521 and 522to receive the filtered signal and thereby to drive an LED unit (notshown) in LED lighting module 530 to emit light

The power supply module of the LED lamp in this embodiment of FIG. 13Dmay be used in LED tube lamp 500 with a dual-end power supply in FIG.13C. It is worth noting that since the power supply module of the LEDlamp comprises rectifying circuits 510 and 540, the power supply moduleof the LED lamp may be used in LED tube lamp 500 with a single-end powersupply in FIG. 13A, to receive an external driving signal (such as theAC supply signal or the AC driving signal described above). The powersupply module of an LED lamp in this embodiment and other embodimentsherein may also be used with a DC driving signal.

FIG. 14A is a schematic diagram of a rectifying circuit according to anembodiment. Referring to FIG. 14A, rectifying circuit 610 includesrectifying diodes 611, 612, 613, and 614, configured to full-waverectify a received signal. Diode 611 has an anode connected to outputterminal 512, and a cathode connected to pin 502. Diode 612 has an anodeconnected to output terminal 512, and a cathode connected to pin 501.Diode 613 has an anode connected to pin 502, and a cathode connected tooutput terminal 511. Diode 614 has an anode connected to pin 501, and acathode connected to output terminal 511.

When pins 501 and 502 receive an AC signal, rectifying circuit 610operates as follows. During the connected AC signal's positive halfcycle, the AC signal is input through pin 501, diode 614, and outputterminal 511 in sequence, and later output through output terminal 512,diode 611, and pin 502 in sequence. During the connected AC signal'snegative half cycle, the AC signal is input through pin 502, diode 613,and output terminal 511 in sequence, and later output through outputterminal 512, diode 612, and pin 501 in sequence. Therefore, during theconnected AC signal's full cycle, the positive pole of the rectifiedsignal produced by rectifying circuit 610 remains at output terminal511, and the negative pole of the rectified signal remains at outputterminal 512. Accordingly, the rectified signal produced or output byrectifying circuit 610 is a full-wave rectified signal.

When pins 501 and 502 are coupled to a DC power supply to receive a DCsignal, rectifying circuit 610 operates as follows. When pin 501 iscoupled to the anode of the DC supply and pin 502 to the cathode of theDC supply, the DC signal is input through pin 501, diode 614, and outputterminal 511 in sequence, and later output through output terminal 512,diode 611, and pin 502 in sequence. When pin 501 is coupled to thecathode of the DC supply and pin 502 to the anode of the DC supply, theDC signal is input through pin 502, diode 613, and output terminal 511in sequence, and later output through output terminal 512, diode 612,and pin 501 in sequence. Therefore, no matter what the electricalpolarity of the DC signal is between pins 501 and 502, the positive poleof the rectified signal produced by rectifying circuit 610 remains atoutput terminal 511, and the negative pole of the rectified signalremains at output terminal 512.

Therefore, rectifying circuit 610 in this embodiment can output orproduce a proper rectified signal regardless of whether the receivedinput signal is an AC or DC signal.

FIG. 14B is a schematic diagram of a rectifying circuit according to anembodiment. Referring to FIG. 14B, rectifying circuit 710 includesrectifying diodes 711 and 712, configured to half-wave rectify areceived signal. Diode 711 has an anode connected to pin 502, and acathode connected to output terminal 511. Diode 712 has an anodeconnected to output terminal 511, and a cathode connected to pin 501.Output terminal 512 may be omitted or grounded depending on actualapplications.

Next, exemplary operation(s) of rectifying circuit 710 is described asfollows.

In one embodiment, during a received AC signal's positive half cycle,the electrical potential at pin 501 is higher than that at pin 502, sodiodes 711 and 712 are both in a cutoff state as being reverse-biased,making rectifying circuit 710 not outputting a rectified signal. Duringa received AC signal's negative half cycle, the electrical potential atpin 501 is lower than that at pin 502, so diodes 711 and 712 are both ina conducting state as being forward-biased, allowing the AC signal to beinput through diode 711 and output terminal 511, and later outputthrough output terminal 512, a ground terminal, or another end of theLED tube lamp not directly connected to rectifying circuit 710.Accordingly, the rectified signal produced or output by rectifyingcircuit 710 is a half-wave rectified signal.

FIG. 14C is a schematic diagram of a rectifying circuit according to anembodiment. Referring to FIG. 14C, rectifying circuit 810 includes arectifying unit 815 and a terminal adapter circuit 541. In thisembodiment, rectifying unit 815 comprises a half-wave rectifier circuitincluding diodes 811 and 812 and configured to half-wave rectify. Diode811 has an anode connected to an output terminal 512, and a cathodeconnected to a half-wave node 819. Diode 812 has an anode connected tohalf-wave node 819, and a cathode connected to an output terminal 511.Terminal adapter circuit 541 is coupled to half-wave node 819 and pins501 and 502, to transmit a signal received at pin 501 and/or pin 502 tohalf-wave node 819. By means of the terminal adapting function ofterminal adapter circuit 541, rectifying circuit 810 allows connectionof two input terminals (connected to pins 501 and 502) and two outputterminals 511 and 512.

In certain embodiments, rectifying circuit 810 operates as follows.

During a received AC signal's positive half cycle, the AC signal may beinput through pin 501 or 502, terminal adapter circuit 541, half-wavenode 819, diode 812, and output terminal 511 in sequence, and lateroutput through another end or circuit of the LED tube lamp. During areceived AC signal's negative half cycle, the AC signal may be inputthrough another end or circuit of the LED tube lamp, and later outputthrough output terminal 512, diode 811, half-wave node 819, terminaladapter circuit 541, and pin 501 or 502 in sequence.

It's worth noting that terminal adapter circuit 541 may comprise aresistor, a capacitor, an inductor, or any combination thereof, forperforming functions of voltage/current regulation or limiting, types ofprotection, current/voltage regulation, etc. Descriptions of thesefunctions are presented below.

In practice, rectifying unit 815 and terminal adapter circuit 541 may beinterchanged in position (as shown in FIG. 14D), without altering thefunction of half-wave rectification. FIG. 14D is a schematic diagram ofa rectifying circuit according to an embodiment. Referring to FIG. 14D,diode 811 has an anode connected to pin 502 and diode 812 has a cathodeconnected to pin 501. A cathode of diode 811 and an anode of diode 812are connected to half-wave node 819. Terminal adapter circuit 541 iscoupled to half-wave node 819 and output terminals 511 and 512. During areceived AC signal's positive half cycle, the AC signal may be inputthrough another end or circuit of the LED tube lamp, and later outputthrough output terminal 512 or 512, terminal adapter circuit 541,half-wave node 819, diode 812, and pin 501 in sequence. During areceived AC signal's negative half cycle, the AC signal may be inputthrough pin 502, diode 811, half-wave node 819, terminal adapter circuit541, and output node 511 or 512 in sequence, and later output throughanother end or circuit of the LED tube lamp.

Terminal adapter circuit 541 in embodiments shown in FIGS. 14C and 14Dmay be omitted and is therefore depicted by a dotted line. If terminaladapter circuit 541 of FIG. 14C is omitted, pins 501 and 502 will becoupled to half-wave node 819. If terminal adapter circuit 541 of FIG.14D is omitted, output terminals 511 and 512 will be coupled tohalf-wave node 819.

Rectifying circuit 510 as shown and explained in FIGS. 14A-D canconstitute or be the rectifying circuit 540 shown in FIG. 13D, as havingpins 503 and 504 for conducting instead of pins 501 and 502.

Next, an explanation follows as to choosing embodiments and theircombinations of rectifying circuits 510 and 540, with reference to FIGS.13B and 13D.

Rectifying circuit 510 in embodiments shown in FIG. 13B may comprise therectifying circuit 610 in FIG. 14A.

Rectifying circuits 510 and 540 in embodiments shown in FIG. 13D mayeach comprise any one of the rectifying circuits in FIGS. 14A-D, andterminal adapter circuit 541 in FIGS. 14C-D may be omitted withoutaltering the rectification function used in an LED tube lamp. Whenrectifying circuits 510 and 540 each comprise a half-wave rectifiercircuit described in FIGS. 14B-D, during a received AC signal's positiveor negative half cycle, the AC signal may be input from one ofrectifying circuits 510 and 540, and later output from the otherrectifying circuit 510 or 540. Further, when rectifying circuits 510 and540 each comprise the rectifying circuit described in FIG. 14C or 14D,or when they comprise the rectifying circuits in FIGS. 14C and 14Drespectively, there may be only one terminal adapter circuit 541 forfunctions of voltage/current regulation or limiting, types ofprotection, current/voltage regulation, etc. within rectifying circuits510 and 540, omitting another terminal adapter circuit 541 withinrectifying circuit 510 or 540.

FIG. 15A is a schematic diagram of a terminal adapter circuit accordingto an embodiment. Referring to FIG. 15A, terminal adapter circuit 641comprises a capacitor 642 having an end connected to pins 501 and 502,and another end connected to half-wave node 819. Capacitor 642 has anequivalent impedance to an AC signal, which impedance increases as thefrequency of the AC signal decreases, and decreases as the frequencyincreases. Therefore, capacitor 642 in terminal adapter circuit 641 inthis embodiment works as a high-pass filter. Further, terminal adaptercircuit 641 is connected in series to an LED unit in the LED tube lamp,producing an equivalent impedance of terminal adapter circuit 641 toperform a current/voltage limiting function on the LED unit, therebypreventing damaging of the LED unit by an excessive voltage acrossand/or current in the LED unit. In addition, choosing the value ofcapacitor 642 according to the frequency of the AC signal can furtherenhance voltage/current regulation.

Terminal adapter circuit 641 may further include a capacitor 645 and/orcapacitor 646. Capacitor 645 has an end connected to half-wave node 819,and another end connected to pin 503. Capacitor 646 has an end connectedto half-wave node 819, and another end connected to pin 504. Forexample, half-wave node 819 may be a common connective node betweencapacitors 645 and 646. And capacitor 642 acting as a current regulatingcapacitor is coupled to the common connective node and pins 501 and 502.In such a structure, series-connected capacitors 642 and 645 existbetween one of pins 501 and 502 and pin 503, and/or series-connectedcapacitors 642 and 646 exist between one of pins 501 and 502 and pin504. Through equivalent impedances of series-connected capacitors,voltages from the AC signal are divided. Referring to FIGS. 13D and 15A,according to ratios between equivalent impedances of theseries-connected capacitors, the voltages respectively across capacitor642 in rectifying circuit 510, filtering circuit 520, and LED lightingmodule 530 can be controlled, making the current flowing through an LEDmodule in LED lighting module 530 being limited within a current rating,and then protecting/preventing filtering circuit 520 and LED lightingmodule 530 from being damaged by excessive voltages.

FIG. 15B is a schematic diagram of a terminal adapter circuit accordingto an embodiment. Referring to FIG. 15B, terminal adapter circuit 741comprises capacitors 743 and 744. Capacitor 743 has an end connected topin 501, and another end connected to half-wave node 819. Capacitor 744has an end connected to pin 502, and another end connected to half-wavenode 819. Compared to terminal adapter circuit 641 in FIG. 15A, terminaladapter circuit 741 has capacitors 743 and 744 in place of capacitor642. Capacitance values of capacitors 743 and 744 may be the same aseach other, or may differ from each other depending on the magnitudes ofsignals to be received at pins 501 and 502.

Similarly, terminal adapter circuit 741 may further comprise a capacitor745 and/or a capacitor 746, respectively connected to pins 503 and 504.For example, each of pins 501 and 502 and each of pins 503 and 504 maybe connected in series to a capacitor, to achieve the functions ofvoltage division and other protections.

FIG. 15C is a schematic diagram of the terminal adapter circuitaccording to an embodiment. Referring to FIG. 15C, terminal adaptercircuit 841 comprises capacitors 842, 843, and 844. Capacitors 842 and843 are connected in series between pin 501 and half-wave node 819.Capacitors 842 and 844 are connected in series between pin 502 andhalf-wave node 819. In such a circuit structure, if any one ofcapacitors 842, 843, and 844 is shorted, there is still at least onecapacitor (of the other two capacitors) between pin 501 and half-wavenode 819 and between pin 502 and half-wave node 819, which performs acurrent-limiting function. Therefore, in the event that a useraccidentally gets an electric shock, this circuit structure will preventan excessive current flowing through and then seriously hurting the bodyof the user.

Similarly, terminal adapter circuit 841 may further comprise a capacitor845 and/or a capacitor 846, respectively connected to pins 503 and 504.For example, each of pins 501 and 502 and each of pins 503 and 504 maybe connected in series to a capacitor, to achieve the functions ofvoltage division and other protections.

FIG. 15D is a schematic diagram of the terminal adapter circuitaccording to an embodiment. Referring to FIG. 15D, terminal adaptercircuit 941 comprises fuses 947 and 948. Fuse 947 has an end connectedto pin 501, and another end connected to half-wave node 819. Fuse 948has an end connected to pin 502, and another end connected to half-wavenode 819. With the fuses 947 and 948, when the current through each ofpins 501 and 502 exceeds a current rating of a corresponding connectedfuse 947 or 948, the corresponding fuse 947 or 948 will accordingly meltand then break the circuit to achieve overcurrent protection.

Each of the embodiments of the terminal adapter circuits as inrectifying circuits 510 and 810 coupled to pins 501 and 502 and shownand explained above can be used or included in the rectifying circuit540 shown in FIG. 13D, as when conductive pins 503 and 504 andconductive pins 501 and 502 are interchanged in position.

Capacitance values of the capacitors in the embodiments of the terminaladapter circuits shown and described above are in some embodiments inthe range, for example, of about 100 pF-100 nF. Also, a capacitor usedin embodiments may be equivalently replaced by two or more capacitorsconnected in series or parallel. For example, each of capacitors 642 and842 may be replaced by two series-connected capacitors, one having acapacitance value chosen from the range, for example of about 1.0 nF toabout 2.5 nF (such as, for example, about 1.5 nF), and the other havinga capacitance value chosen from the range, for example of about 1.5 nFto about 3.0 nF (such as, for example, about 2.2 nF).

FIG. 16A is a block diagram of a filtering circuit according to anembodiment. Rectifying circuit 510 is shown in FIG. 16A for illustratingits connection with other components, without intending filteringcircuit 520 to include rectifying circuit 510. Referring to FIG. 16A,filtering circuit 520 includes a filtering unit 523 coupled torectifying output terminals 511 and 512 to receive, and to filter outripples of, a rectified signal from rectifying circuit 510, therebyoutputting a filtered signal whose waveform is smoother than therectified signal. Filtering circuit 520 may further comprise anotherfiltering unit 524 coupled between a rectifying circuit and a pin, whichare for example rectifying circuit 510 and pin 501, rectifying circuit510 and pin 502, rectifying circuit 540 and pin 503, or rectifyingcircuit 540 and pin 504. Filtering unit 524 is for filtering of aspecific frequency, in order to filter out a specific frequencycomponent of an external driving signal. In this embodiment of FIG. 16A,filtering unit 524 is coupled between rectifying circuit 510 and pin501. Filtering circuit 520 may further comprise another filtering unit525 coupled between one of pins 501 and 502 and a diode of rectifyingcircuit 510, or between one of pins 503 and 504 and a diode ofrectifying circuit 540, for reducing or filtering out electromagneticinterference (EMI). In this embodiment, filtering unit 525 is coupledbetween pin 501 and a diode (not shown in FIG. 16A) of rectifyingcircuit 510. Since filtering units 524 and 525 may be present or omitteddepending on actual circumstances of their uses, they are depicted by adotted line in FIG. 16A.

FIG. 16B is a schematic diagram of a filtering unit according to anembodiment. Referring to FIG. 16B, filtering unit 623 includes acapacitor 625 having an end coupled to output terminal 511 and afiltering output terminal 521 and another end coupled to output terminal512 and a filtering output terminal 522, and is configured to low-passfilter a rectified signal from output terminals 511 and 512, so as tofilter out high-frequency components of the rectified signal and therebyoutput a filtered signal at output terminals 521 and 522.

FIG. 16C is a schematic diagram of a filtering unit according to anembodiment. Referring to FIG. 16C, filtering unit 723 comprises a pifilter circuit including a capacitor 725, an inductor 726, and acapacitor 727. As is well known, a pi filter circuit looks like thesymbol n in its shape or structure. Capacitor 725 has an end connectedto output terminal 511 and coupled to output terminal 521 throughinductor 726, and has another end connected to output terminals 512 and522. Inductor 726 is coupled between output terminals 511 and 521.Capacitor 727 has an end connected to output terminal 521 and coupled tooutput terminal 511 through inductor 726, and has another end connectedto output terminals 512 and 522.

As seen between output terminals 511 and 512 and output terminals 521and 522, filtering unit 723 compared to filtering unit 623 in FIG. 16Badditionally has inductor 726 and capacitor 727, which are likecapacitor 725 in performing low-pass filtering. Therefore, filteringunit 723 in this embodiment compared to filtering unit 623 in FIG. 16Bhas a better ability to filter out high-frequency components to output afiltered signal with a smoother waveform.

Inductance values of inductor 726 in the embodiment described above arechosen in some embodiments in the range of about 10 nH to about 10 mH.And capacitance values of capacitors 625, 725, and 727 in theembodiments described above are chosen in some embodiments in the range,for example, of about 100 pF to about 1 uF.

FIG. 16D is a schematic diagram of the filtering unit according to anembodiment. Referring to FIG. 16D, filtering unit 824 includes acapacitor 825 and an inductor 828 connected in parallel. Capacitor 825has an end coupled to pin 501, and another end coupled to rectifyingoutput terminal 511, and is configured to high-pass filter an externaldriving signal input at pin 501, so as to filter out low-frequencycomponents of the external driving signal. Inductor 828 has an endcoupled to pin 501 and another end coupled to rectifying output terminal511, and is configured to low-pass filter an external driving signalinput at pin 501, so as to filter out high-frequency components of theexternal driving signal. Therefore, the combination of capacitor 825 andinductor 828 works to present high impedance to an external drivingsignal at one or more specific frequencies. In some embodiments, theparallel-connected capacitor and inductor present a peak equivalentimpedance to the external driving signal at a specific frequency.

Through appropriately choosing a capacitance value of capacitor 825 andan inductance value of inductor 828, a center frequency f on thehigh-impedance band may be set at a specific value given by

${f = \frac{1}{2\pi \sqrt{LC}}},$

where L denotes inductance of inductor 828 and C denotes capacitance ofcapacitor 825. The center frequency may be in the range of, for example,about 20˜30 kHz. In some embodiments, the center frequency may be about25 kHz. And an LED lamp with filtering unit 824 is able to be certifiedunder safety standards, for a specific center frequency, as provided byUnderwriters Laboratories (UL).

It's worth noting that filtering unit 824 may further comprise aresistor 829, coupled between pin 501 and filtering output terminal 511.In FIG. 16D, resistor 829 is connected in series to theparallel-connected capacitor 825 and inductor 828. For example, resistor829 may be coupled between pin 501 and parallel-connected capacitor 825and inductor 828, or may be coupled between filtering output terminal511 and parallel-connected capacitor 825 and inductor 828. In thisembodiment, resistor 829 is coupled between pin 501 andparallel-connected capacitor 825 and inductor 828. Further, resistor 829is configured for adjusting the quality factor (Q) of the LC circuitcomprising capacitor 825 and inductor 828, to better adapt filteringunit 824 to application environments with different quality factorrequirements. Since resistor 829 is an optional component, it isdepicted in a dotted line in FIG. 16D.

Capacitance values of capacitor 825 may be, for example, in the range ofabout 10 nF-2 uF. Inductance values of inductor 828 may be smaller than2 mH. In some embodiments, inductance values of inductor 828 may besmaller than 1 mH. Resistance values of resistor 829 may be larger than50 ohms. In some embodiments, resistance values of resistor 829 may belarger than 500 ohms.

Besides the filtering circuits shown and described in the aboveembodiments, traditional low-pass or band-pass filters can be used asthe filtering unit in the filtering circuit.

FIG. 16E is a schematic diagram of a filtering unit according to anembodiment. Referring to FIG. 16E, in this embodiment filtering unit 925is disposed in rectifying circuit 610 as shown in FIG. 14A, and isconfigured for reducing the EMI (Electromagnetic interference) caused byrectifying circuit 610 and/or other circuits. In this embodiment,filtering unit 925 includes an EMI-reducing capacitor coupled betweenpin 501 and the anode of rectifying diode 613, and also between pin 502and the anode of rectifying diode 614, to reduce the EMI associated withthe positive half cycle of the AC driving signal received at pins 501and 502. The EMI-reducing capacitor of filtering unit 925 is alsocoupled between pin 501 and the cathode of rectifying diode 611, andbetween pin 502 and the cathode of rectifying diode 612, to reduce theEMI associated with the negative half cycle of the AC driving signalreceived at pins 501 and 502. In some embodiments, rectifying circuit610 comprises a full-wave bridge rectifier circuit including fourrectifying diodes 611, 612, 613, and 614. The full-wave bridge rectifiercircuit has a first filtering node connecting an anode and a cathoderespectively of two diodes 613 and 611 of the four rectifying diodes611, 612, 613, and 614, and a second filtering node connecting an anodeand a cathode respectively of the other two diodes 614 and 612 of thefour rectifying diodes 611, 612, 613, and 614. And the EMI-reducingcapacitor of the filtering unit 925 is coupled between the firstfiltering node and the second filtering node.

Similarly, with reference to FIGS. 14C, and 15A-15C, any capacitor ineach of the circuits in FIGS. 15A-15C is coupled between pins 501 and502 (or pins 503 and 504) and any diode in FIG. 14C, so any or eachcapacitor in FIGS. 15A-15C can work as an EMI-reducing capacitor toachieve the function of reducing EMI. For example, rectifying circuit510 in FIGS. 13B and 13D may comprise a half-wave rectifier circuitincluding two rectifying diodes and having a half-wave node connectingan anode and a cathode respectively of the two rectifying diodes, andany or each capacitor in FIGS. 15A-15C may be coupled between thehalf-wave node and at least one of the first pin and the second pin. Andrectifying circuit 540 in FIG. 13D may comprise a half-wave rectifiercircuit including two rectifying diodes and having a half-wave nodeconnecting an anode and a cathode respectively of the two rectifyingdiodes, and any or each capacitor in FIGS. 15A-15C may be coupledbetween the half-wave node and at least one of the third pin and thefourth pin.

It's worth noting that the EMI-reducing capacitor in the embodiment ofFIG. 16E may also act as capacitor 825 in filtering unit 824, so that incombination with inductor 828 the capacitor 825 performs the functionsof reducing EMI and presenting high impedance to an external drivingsignal at specific frequencies. For example, when the rectifying circuitcomprises a full-wave bridge rectifier circuit, capacitor 825 offiltering unit 824 may be coupled between the first filtering node andthe second filtering node of the full-wave bridge rectifier circuit.When the rectifying circuit comprises a half-wave rectifier circuit,capacitor 825 of filtering unit 824 may be coupled between the half-wavenode of the half-wave rectifier circuit and at least one of the firstpin and the second pin.

FIG. 17A is a schematic diagram of an LED module according to anembodiment. Referring to FIG. 17A, LED module 630 has an anode connectedto the filtering output terminal 521, has a cathode connected to thefiltering output terminal 522, and comprises at least one LED unit 632.When two or more LED units are included, they are connected in parallel.The anode of each LED unit 632 is connected to, or forms, the anode ofLED module 630 and thus is connected to output terminal 521, and thecathode of each LED unit 632 is connected to, or forms, the cathode ofLED module 630 and thus is connected to output terminal 522. Each LEDunit 632 includes at least one LED 631. When multiple LEDs 631 areincluded in an LED unit 632, they are connected in series, with theanode of the first LED 631 connected to, or forming, the anode of thisLED unit 632, and the cathode of the first LED 631 connected to the nextor second LED 631. And the anode of the last LED 631 in this LED unit632 is connected to the cathode of a previous LED 631, with the cathodeof the last LED 631 connected to, or forming, the cathode of this LEDunit 632.

According to certain embodiments, LED module 630 may produce a currentdetection signal S531 reflecting a magnitude of current through LEDmodule 630 and used for controlling or detecting on the LED module 630.As described herein, an LED unit may refer to a single string of LEDsarranged in series, and an LED module may refer to a single LED unit, ora plurality of LED units connected to a same two nodes (e.g., arrangedin parallel). For example, the LED light strip 2 described above may bean LED module and/or LED unit.

FIG. 17B is a schematic diagram of an LED module according to oneembodiment. Referring to FIG. 17B, LED module 630 has an anode connectedto the filtering output terminal 521, has a cathode connected to thefiltering output terminal 522, and comprises at least two LED units 732,with the anode of each LED unit 732 connected to, or forming, the anodeof LED module 630, and the cathode of each LED unit 732 connected to, orforming, the cathode of LED module 630. Each LED unit 732 includes atleast two LEDs 731 connected in the same way as described in FIG. 17A.For example, the anode of the first LED 731 in an LED unit 732 isconnected to, or forms, the anode of this LED unit 732 that it is a partof, the cathode of the first LED 731 is connected to the anode of thenext or second LED 731, and the cathode of the last LED 731 is connectedto, or forms, the cathode of this LED unit 732 that it is a part of.Further, LED units 732 in the LED module 630 are connected to each otherin this embodiment. All of the n-th LEDs 731 respectively of the LEDunits 732 are connected by every anode of every n-th LED 731 in the LEDunits 732, and by every cathode of every n-th LED 731, where n is apositive integer. In this way, the LEDs in LED module 630 in thisembodiment are connected in the form of a mesh.

The number of LEDs 731 included by an LED unit 732 may be in the rangeof 15-25. In some embodiments, the number of LEDs 731 may be in therange of 18-22.

FIG. 17C is a plan view of a circuit layout of an LED module accordingto one embodiment. Referring to FIG. 17C, in this embodiment LEDs 831are connected in the same way as described in FIG. 17B, and three LEDunits are assumed in LED module 630 and described as follows forillustration. A positive conductive line 834 and a negative conductiveline 835 are to receive a driving signal, for supplying power to theLEDs 831. For example, positive conductive line 834 may be coupled tothe filtering output terminal 521 of the filtering circuit 520 describedabove, and negative conductive line 835 coupled to the filtering outputterminal 522 of the filtering circuit 520, to receive a filtered signal.For the convenience of illustration, all three of the n-th LEDs 831respectively of the three LED units are grouped as an LED set 833 inFIG. 17C.

Positive conductive line 834 connects the three first LEDs 831respectively of the leftmost three LED units, at the anodes on the leftsides of the three first LEDs 831 as shown in the leftmost LED set 833of FIG. 17C. Negative conductive line 835 connects the three last LEDs831 respectively of the leftmost three LED units, at the cathodes on theright sides of the three last LEDs 831 as shown in the rightmost LED set833 of FIG. 17C. And of the three LED units, the cathodes of the threefirst LEDs 831, the anodes of the three last LEDs 831, and the anodesand cathodes of all the remaining LEDs 831 are connected by conductivelines or parts 839, also referred to as internal conductive connectors.

For example, the anodes of the three LEDs 831 in the leftmost LED set833 may be connected together by positive conductive line 834, and theircathodes may be connected together by a leftmost conductive part 839.The anodes of the three LEDs 831 in the second leftmost LED set 833 arealso connected together by the leftmost conductive part 839, whereastheir cathodes are connected together by a second, next-leftmostconductive part 839. Since the cathodes of the three LEDs 831 in theleftmost LED set 833 and the anodes of the three LEDs 831 in the second,next-leftmost LED set 833 are connected together by the same leftmostconductive part 839, in each of the three LED units the cathode of thefirst LED 831 is connected to the anode of the next or second LED 831,with the remaining LEDs 831 also being connected in the same way.Accordingly, all the LEDs 831 of the three LED units are connected toform the mesh as shown in FIG. 17B. The LED module shown in FIG. 17C mayform an LED light strip 2 such as described above.

In the embodiment shown in FIG. 17C, the length 836 (e.g., length alonga first direction that is a length direction of the LED light strip 2and lamp tube) of a portion of each conductive part 839 that immediatelyconnects to the anode of an LED 831 is smaller than the length 837 ofanother portion of each conductive part 839 that immediately connects tothe cathode of an LED 831, making the area of the latter portionimmediately connecting to the cathode larger than that of the formerportion immediately connecting to the anode. The length 837 may besmaller than a length 838 of a portion of each conductive part 839 thatimmediately connects the cathode of an LED 831 and the anode of the nextLED 831, making the area of the portion of each conductive part 839 thatimmediately connects a cathode and an anode larger than the area of anyother portion of each conductive part 839 that immediately connects toonly a cathode or an anode of an LED 831. Due to the length differencesand area differences, this layout structure improves heat dissipation ofthe LEDs 831.

In some embodiments, positive conductive line 834 includes a lengthwiseportion 834 a, and negative conductive line 835 includes a lengthwiseportion 835 a, which are conducive to making the LED module have apositive “+” connective portion and a negative “−” connective portion ateach of the two ends of the LED module, as shown in FIG. 17C. Such alayout structure allows for coupling certain of the various circuits ofthe power supply module of the LED lamp, including e.g. filteringcircuit 520 and rectifying circuits 510 and 540, to the LED modulethrough the positive connective portion and/or the negative connectiveportion at each or both ends of the LED lamp. In some embodiments, thelayout structure increases the flexibility in arranging actual circuitsin the LED lamp.

FIG. 17D is a plan view of a circuit layout of the LED module accordingto another embodiment. Referring to FIG. 17D, in this embodiment LEDs931 are connected in the same way as described in FIG. 17A, and threeLED units each including 7 LEDs 931 are assumed in LED module 630 anddescribed as follows for illustration. A positive conductive line 934and a negative conductive line 935 are to receive a driving signal, forsupplying power to the LEDs 931. For example, positive conductive line934 may be coupled to the filtering output terminal 521 of the filteringcircuit 520 described above, and negative conductive line 935 coupled tothe filtering output terminal 522 of the filtering circuit 520, toreceive a filtered signal. For the convenience of illustration, allseven LEDs 931 of each of the three LED units are grouped as an LED set932 in FIG. 17D. For example, there are three LED sets 932 correspondingto the three LED units.

Positive conductive line 934 connects to the anode on the left side ofthe first or leftmost LED 931 of each of the three LED sets 932.Negative conductive line 935 connects to the cathode on the right sideof the last or rightmost LED 931 of each of the three LED sets 932. Ineach LED set 932, of two consecutive LEDs 931 the LED 931 on the lefthas a cathode connected by a conductive part 939 to an anode of the LED931 on the right. By such a layout, the LEDs 931 of each LED set 932 areconnected in series.

In some embodiments, the conductive part 939 may be used to connect ananode and a cathode respectively of two consecutive LEDs 931. Negativeconductive line 935 connects to the cathode of the last or rightmost LED931 of each of the three LED sets 932. And positive conductive line 934connects to the anode of the first or leftmost LED 931 of each of thethree LED sets 932. Therefore, as shown in FIG. 17D, the length (andthus area) of the conductive part 939 is larger than that of the portionof negative conductive line 935 immediately connecting to a cathode,which length (and thus area) is then larger than that of the portion ofpositive conductive line 934 immediately connecting to an anode. Forexample, the length 938 of the conductive part 939 may be larger thanthe length 937 of the portion of negative conductive line 935immediately connecting to a cathode of an LED 931, which length 937 isthen larger than the length 936 of the portion of positive conductiveline 934 immediately connecting to an anode of an LED 931. Such a layoutstructure improves heat dissipation of the LEDs 931 in LED module 630.

Positive conductive line 934 may include a lengthwise portion 934 a, andnegative conductive line 935 may include a lengthwise portion 935 a,which are conducive to making the LED module have a positive “+”connective portion and a negative “−” connective portion at each of thetwo ends of the LED module, as shown in FIG. 17D. Such a layoutstructure allows for coupling certain of the various circuits of thepower supply module of the LED lamp, including e.g. filtering circuit520 and rectifying circuits 510 and 540, to the LED module through thepositive connective portion 934 a and/or the negative connective portion935 a at each or both ends of the LED lamp.

The positive conductive lines (834 or 934) may be characterized asincluding two end terminals at opposite ends, a plurality of padsbetween the two end terminals and for contacting and/or supplying powerto LEDs (e.g., anodes of LEDs), and a wire portion, which may be anelongated conducive line extending along a length of an LED light stripand electrically connecting the two end terminals to the plurality ofpads. Similarly, the negative conductive lines (835 or 935) may becharacterized as including two end terminals at opposite ends, aplurality of pads between the two end terminals and for contactingand/or supplying power to LEDs (e.g., cathodes of LEDs), and a wireportion, which may be an elongated conducive line extending along alength of an LED light strip and electrically connecting the two endterminals to the plurality of pads. In some embodiments, the layoutstructure described above increases the flexibility in arranging actualcircuits in the LED lamp.

Further, the circuit layouts as shown in FIGS. 17C and 17D may beimplemented with a bendable circuit sheet or substrate, which may evenbe called flexible circuit board. The circuit layouts may be implementedfor one of the exemplary LED light strips described previously, forexample, to serve as a circuit board or sheet for the LED light strip onwhich the LED light sources are disposed. For example, the bendablecircuit sheet may comprise one conductive layer where positiveconductive line 834, including positive lengthwise portion 834 a,negative conductive line 835, including negative lengthwise portion 835a, and conductive parts 839 shown in FIG. 17C, and positive conductiveline 934, positive lengthwise portion 934 a, negative conductive line935, negative lengthwise portion 935 a, and conductive parts 939 shownin FIG. 17D are formed. For example, the different conductive patternsmay be formed by an etching method.

FIG. 17E is a plan view of a circuit layout of an LED module accordingto another embodiment. The layout structures of the LED module in FIGS.17E and 17C each correspond to the same way of connecting LEDs 831 asthat shown in FIG. 17B, but the layout structure in FIG. 17E comprisestwo conductive layers, instead of only one conductive layer for formingthe circuit layout as shown in FIG. 17C. Referring to FIG. 17E, the maindifference from the layout in FIG. 17C is that positive conductive line834 and negative conductive line 835 have a lengthwise portion 834 a anda lengthwise portion 835 a, respectively, that are formed in a secondconductive layer instead. The difference is elaborated as follows.

Referring to FIG. 17E, the bendable circuit sheet of the LED modulecomprises a first conductive layer 2 a and a second conductive layer 2 celectrically insulated from each other by a dielectric layer 2 b (notshown). Of the two conductive layers, positive conductive line 834,negative conductive line 835, and conductive parts 839 in FIG. 17E areformed in first conductive layer 2 a by the method of etching forelectrically connecting the plurality of LED components 831 e.g. in aform of a mesh, whereas positive lengthwise portion 834 a and negativelengthwise portion 835 a are formed in second conductive layer 2 c byetching for electrically connecting to (the filtering output terminalof) the filtering circuit. Further, positive conductive line 834 andnegative conductive line 835 in first conductive layer 2 a have viapoints 834 b and via points 835 b, respectively, for connecting tosecond conductive layer 2 c. And positive lengthwise portion 834 a andnegative lengthwise portion 835 a in second conductive layer 2 c havevia points 834 c and via points 835 c, respectively. Via points 834 bare positioned corresponding to via points 834 c, for connectingpositive conductive line 834 and positive lengthwise portion 834 a. Viapoints 835 b are positioned corresponding to via points 835 c, forconnecting negative conductive line 835 and negative lengthwise portion835 a. In some embodiments, the two conductive layers may be connectedby forming a hole connecting each via point 834 b and a correspondingvia point 834 c, and to form a hole connecting each via point 835 b anda corresponding via point 835 c, with the holes extending through thetwo conductive layers and the dielectric layer in-between. Positiveconductive line 834 and positive lengthwise portion 834 a can beelectrically connected, for example, by welding metallic part(s) throughthe connecting hole(s), and negative conductive line 835 and negativelengthwise portion 835 a can be electrically connected, for example, bywelding metallic part(s) through the connecting hole(s).

Similarly, the layout structure of the LED module in FIG. 17D mayalternatively have positive lengthwise portion 934 a and negativelengthwise portion 935 a disposed in a second conductive layer, toconstitute a two-layer layout structure.

It's worth noting that the thickness of the second conductive layer of atwo-layer bendable circuit sheet is in some embodiments larger than thatof the first conductive layer, in order to reduce the voltage drop orloss along each of the positive lengthwise portion and the negativelengthwise portion disposed in the second conductive layer. Compared toa one-layer bendable circuit sheet, since a positive lengthwise portionand a negative lengthwise portion are disposed in a second conductivelayer in a two-layer bendable circuit sheet, the width (between twolengthwise sides) of the two-layer bendable circuit sheet is or can bereduced. On the same fixture or plate in a production process, themaximum number of bendable circuit sheets each with a shorter width thatcan be laid together is larger than the maximum number of bendablecircuit sheets each with a longer width that can be laid together. Insome embodiments, adopting a bendable circuit sheet with a shorter widthcan increase the efficiency of production of the LED module. Andreliability in the production process, such as the accuracy of weldingposition when welding (materials on) the LED components, can also beimproved, because a two-layer bendable circuit sheet can better maintainits shape.

As a variant of the above embodiments, an exemplary LED tube lamp mayhave at least some of the electronic components of its power supplymodule disposed on a light strip of the LED tube lamp. For example, thetechnique of printed electronic circuit (PEC) can be used to print,insert, or embed at least some of the electronic components onto the LEDlight strip (e.g., as opposed to being on a separate circuit boardconnected to the LED light strip).

In one embodiment, all electronic components of the power supply moduleare disposed directly on the LED light strip. For example, theproduction process may include or proceed with the following steps:preparation of the circuit substrate (e.g. preparation of a flexibleprinted circuit board); ink jet printing of metallic nano-ink; ink jetprinting of active and passive components (as of the power supplymodule); drying/sintering; ink jet printing of interlayer bumps;spraying of insulating ink; ink jet printing of metallic nano-ink; inkjet printing of active and passive components (to sequentially form theincluded layers); spraying of surface bond pad(s); and spraying ofsolder resist against LED components. The production process may bedifferent, however, and still result in some or all electroniccomponents of the power supply module being disposed directly on the LEDlight strip.

In certain embodiments, if all electronic components of the power supplymodule are disposed on the light strip, electrical connection betweenterminal pins of the LED tube lamp and the light strip may be achievedby connecting the pins to conductive lines which are welded to ends ofthe light strip. In this case, another substrate for supporting thepower supply module is not used, thereby allowing of an improved designor arrangement in the end cap(s) of the LED tube lamp. In someembodiments, (components of) the power supply module are disposed at twoends of the light strip, in order to significantly reduce the impact ofheat generated from the power supply module's operations on the LEDcomponents. In this embodiment, since no substrate other than the lightstrip is used to support the power supply module in this case, the totalamount of welding or soldering can be significantly reduced, improvingthe general reliability of the power supply module.

Another case is that some of all electronic components of the powersupply module, such as some resistors and/or smaller size capacitors,are printed onto the light strip, and some bigger size components, suchas some inductors and/or electrolytic capacitors, are disposed in theend cap(s) (e.g., on another substrate). The production process of thelight strip in this case may be the same as that described above. And inthis case disposing some of all electronic components on the light stripis conducive to achieving a reasonable layout of the power supply modulein the LED tube lamp, which may allow of an improved design in the endcap(s).

As a variant embodiment of the above, electronic components of the powersupply module may be disposed on the light strip by a method ofembedding or inserting, e.g. by embedding the components onto a bendableor flexible light strip. In some embodiments, this embedding may berealized by a method using copper-clad laminates (CCL) for forming aresistor or capacitor; a method using ink related to silkscreenprinting; or a method of ink jet printing to embed passive components,wherein an ink jet printer is used to directly print inks to constitutepassive components and related functionalities to intended positions onthe light strip. Then through treatment by ultraviolet (UV) light ordrying/sintering, the light strip is formed where passive components areembedded. The electronic components embedded onto the light stripinclude for example resistors, capacitors, and inductors. In otherembodiments, active components also may be embedded. Through embeddingsome components onto the light strip, a reasonable layout of the powersupply module can be achieved to allow of an improved design in the endcap(s), because the surface area on a printed circuit board used forcarrying components of the power supply module is reduced or smaller,and as a result the size, weight, and thickness of the resulting printedcircuit board for carrying components of the power supply module is alsosmaller or reduced. Also in this situation since welding points on theprinted circuit board for welding resistors and/or capacitors if theywere not to be disposed on the light strip are no longer used, thereliability of the power supply module is improved, in view of the factthat these welding points are most liable to (cause or incur) faults,malfunctions, or failures. Further, the length of conductive lines usedfor connecting components on the printed circuit board is therefore alsoreduced, which allows of a more compact layout of components on theprinted circuit board and thus improving the functionalities of thesecomponents.

Next, methods to produce embedded capacitors and resistors are explainedas follows.

Usually, methods for manufacturing embedded capacitors employ or involvea concept called distributed or planar capacitance. The manufacturingprocess may include the following step(s). On a substrate of a copperlayer a very thin insulation layer is applied or pressed, which is thengenerally disposed between a pair of layers including a power conductivelayer and a ground layer. The very thin insulation layer makes thedistance between the power conductive layer and the ground layer veryshort. A capacitance resulting from this structure can also be realizedby a conventional technique of a plated-through hole. Basically, thisstep is used to create this structure comprising a big parallel-platecapacitor on a circuit substrate.

Of products of high electrical capacity, certain types of productsemploy distributed capacitances, and other types of products employseparate embedded capacitances. Through putting or adding a highdielectric-constant material such as barium titanate into the insulationlayer, the high electrical capacity is achieved.

A usual method for manufacturing embedded resistors employ conductive orresistive adhesive. This may include, for example, a resin to whichconductive carbon or graphite is added, which may be used as an additiveor filler. The additive resin is silkscreen printed to an objectlocation, and is then after treatment laminated inside the circuitboard. The resulting resistor is connected to other electroniccomponents through plated-through holes or microvias. Another method iscalled Ohmega-Ply, by which a two metallic layer structure of a copperlayer and a thin nickel alloy layer constitutes a layer resistorrelative to a substrate. Then through etching the copper layer andnickel alloy layer, different types of nickel alloy resistors withcopper terminals can be formed. These types of resistor are eachlaminated inside the circuit board.

In one embodiment, conductive wires/lines are directly printed in alinear layout on an inner surface of the LED glass lamp tube, with LEDcomponents directly attached on the inner surface and electricallyconnected by the conductive wires. In some embodiments, the LEDcomponents in the form of chips are directly attached over theconductive wires on the inner surface, and connective points are atterminals of the wires for connecting the LED components and the powersupply module. After being attached, the LED chips may have fluorescentpowder applied or dropped thereon, for producing white light or light ofother color by the operating LED tube lamp.

Luminous efficacy of the LED or LED component may be 80 lm/W or above.In some embodiments, luminous efficiency of the LED or LED component maybe 120 lm/W or above. Certain more optimal embodiments may include aluminous efficacy of the LED or LED component of 160 lm/W or above.White light emitted by an LED component, such as those in the disclosedembodiments, may be produced by mixing fluorescent powder with themonochromatic light emitted by a monochromatic LED chip. The white lightin its spectrum has major wavelength ranges of 430-460 nm and 550-560nm, or major wavelength ranges of 430-460 nm, 540-560 nm, and 620-640nm.

FIG. 18A is a block diagram of an LED lamp according to an embodiment.As shown in FIG. 18A, a power supply module of the LED lamp includesrectifying circuits 510 and 540, a filtering circuit 520, and a drivingcircuit 1530, and an LED lighting module 530 is composed of the drivingcircuit 1530 and an LED module 630. LED lighting module 530 in thisembodiment comprises a driving circuit 1530 and an LED module 630.According to the above description in FIG. 13D, driving circuit 1530 inFIG. 18A comprises a DC-to-DC converter circuit, and is coupled tofiltering output terminals 521 and 522 to receive a filtered signal andthen perform power conversion for converting the filtered signal into adriving signal at driving output terminals 1521 and 1522. The LED module630 is coupled to driving output terminals 1521 and 1522 to receive thedriving signal for emitting light. In some embodiments, the current ofLED module 630 is stabilized at an objective current value. Descriptionsof this LED module 630 are the same as those provided above withreference to FIGS. 17A-17D.

It's worth noting that rectifying circuit 540 is an optional element andtherefore can be omitted, so it is depicted in a dotted line in FIG.18A. Accordingly, LED lighting module 530 in embodiments of FIGS. 18A,18C, and 18E may comprise a driving circuit 1530 and an LED module 630.Therefore, the power supply module of the LED lamp in this embodimentcan be used with a single-end power supply coupled to one end of the LEDlamp, and can be used with a dual-end power supply coupled to two endsof the LED lamp. With a single-end power supply, examples of the LEDlamp include an LED light bulb, a personal area light (PAL), etc.

FIG. 18B is a block diagram of an exemplary driving circuit according toone embodiment. Referring to FIG. 18B, the driving circuit includes acontroller 1531, and a conversion circuit 1532 for power conversionbased on a current source, for driving the LED module to emit light.Conversion circuit 1532 includes a switching circuit 1535 and an energystorage circuit 1538. And conversion circuit 1532 is coupled tofiltering output terminals 521 and 522 to receive and then convert afiltered signal, under the control by controller 1531, into a drivingsignal at driving output terminals 1521 and 1522 for driving the LEDmodule. Under the control by controller 1531, the driving signal outputby conversion circuit 1532 comprises a steady current, making the LEDmodule emitting steady light.

FIG. 18C is a schematic diagram of an exemplary driving circuitaccording to one embodiment. Referring to FIG. 18C, a driving circuit1630 in this embodiment comprises a buck DC-to-DC converter circuithaving a controller 1631 and a converter circuit. The converter circuitincludes an inductor 1632, a diode 1633 for “freewheeling” of current, acapacitor 1634, and a switch 1635. Driving circuit 1630 is coupled tofiltering output terminals 521 and 522 to receive and then convert afiltered signal into a driving signal for driving an LED moduleconnected between driving output terminals 1521 and 1522.

In this embodiment, switch 1635 comprises a metal-oxide-semiconductorfield-effect transistor (MOSFET) and has a first terminal coupled to theanode of freewheeling diode 1633, a second terminal coupled to filteringoutput terminal 522, and a control terminal coupled to controller 1631used for controlling current conduction or cutoff between the first andsecond terminals of switch 1635. Driving output terminal 1521 isconnected to filtering output terminal 521, and driving output terminal1522 is connected to an end of inductor 1632, which has another endconnected to the first terminal of switch 1635. Capacitor 1634 iscoupled between driving output terminals 1521 and 1522, to stabilize thevoltage between driving output terminals 1521 and 1522. Freewheelingdiode 1633 has a cathode connected to driving output terminal 1521.

Next, a description follows as to an exemplary operation of drivingcircuit 1630.

Controller 1631 is configured for determining when to turn switch 1635on (in a conducting state) or off (in a cutoff state), according to acurrent detection signal S535 and/or a current detection signal S531.For example, in some embodiments, controller 1631 is configured tocontrol the duty cycle of switch 1635 being on and switch 1635 beingoff, in order to adjust the size or magnitude of the driving signal.Current detection signal S535 represents the magnitude of currentthrough switch 1635. Current detection signal S531 represents themagnitude of current through the LED module coupled between drivingoutput terminals 1521 and 1522. The controller 1631 may control the dutycycle of the switch 1635 being on and off, based on, for example, amagnitude of a current detected based on current detection signal S531or S535. As such, when the magnitude is above a threshold, the switchmay be off (cutoff state) for more time, and when magnitude goes belowthe threshold, the switch may be on (conducting state) for more time.According to any of current detection signal S535 and current detectionsignal S531, controller 1631 can obtain information on the magnitude ofpower converted by the converter circuit. When switch 1635 is switchedon, a current of a filtered signal is input through filtering outputterminal 521, and then flows through capacitor 1634, driving outputterminal 1521, the LED module, inductor 1632, and switch 1635, and thenflows out from filtering output terminal 522. During this flowing ofcurrent, capacitor 1634 and inductor 1632 are performing storing ofenergy. On the other hand, when switch 1635 is switched off, capacitor1634 and inductor 1632 perform releasing of stored energy by a currentflowing from freewheeling capacitor 1633 to driving output terminal 1521to make the LED module continuing to emit light.

It's worth noting that capacitor 1634 is an optional element, so it canbe omitted and is thus depicted in a dotted line in FIG. 18C. In someapplication environments, the natural characteristic of an inductor tooppose instantaneous change in electric current passing through theinductor may be used to achieve the effect of stabilizing the currentthrough the LED module, thus omitting capacitor 1634.

FIG. 18D is a schematic diagram of an exemplary driving circuitaccording to one embodiment. Referring to FIG. 18D, a driving circuit1730 in this embodiment comprises a boost DC-to-DC converter circuithaving a controller 1731 and a converter circuit. The converter circuitincludes an inductor 1732, a diode 1733 for “freewheeling” of current, acapacitor 1734, and a switch 1735. Driving circuit 1730 is configured toreceive and then convert a filtered signal from filtering outputterminals 521 and 522 into a driving signal for driving an LED modulecoupled between driving output terminals 1521 and 1522.

Inductor 1732 has an end connected to filtering output terminal 521, andanother end connected to the anode of freewheeling diode 1733 and afirst terminal of switch 1735, which has a second terminal connected tofiltering output terminal 522 and driving output terminal 1522.Freewheeling diode 1733 has a cathode connected to driving outputterminal 1521. And capacitor 1734 is coupled between driving outputterminals 1521 and 1522.

Controller 1731 is coupled to a control terminal of switch 1735, and isconfigured for determining when to turn switch 1735 on (in a conductingstate) or off (in a cutoff state), according to a current detectionsignal S535 and/or a current detection signal S531. When switch 1735 isswitched on, a current of a filtered signal is input through filteringoutput terminal 521, and then flows through inductor 1732 and switch1735, and then flows out from filtering output terminal 522. During thisflowing of current, the current through inductor 1732 increases withtime, with inductor 1732 being in a state of storing energy, whilecapacitor 1734 enters a state of releasing energy, making the LED modulecontinuing to emit light. On the other hand, when switch 1735 isswitched off, inductor 1732 enters a state of releasing energy as thecurrent through inductor 1732 decreases with time. In this state, thecurrent through inductor 1732 then flows through freewheeling diode1733, capacitor 1734, and the LED module, while capacitor 1734 enters astate of storing energy.

It's worth noting that capacitor 1734 is an optional element, so it canbe omitted, as is depicted by the dotted line in FIG. 18D. Whencapacitor 1734 is omitted and switch 1735 is switched on, the current ofinductor 1732 does not flow through the LED module, making the LEDmodule not emit light; but when switch 1735 is switched off, the currentof inductor 1732 flows through freewheeling diode 1733 to reach the LEDmodule, making the LED module emit light. Therefore, by controlling thetime that the LED module emits light, and the magnitude of currentthrough the LED module, the average luminance of the LED module can bestabilized to be above a defined value, thus also achieving the effectof emitting a steady light.

FIG. 18E is a schematic diagram of an exemplary driving circuitaccording to one embodiment. Referring to FIG. 18E, a driving circuit1830 in this embodiment comprises a buck DC-to-DC converter circuithaving a controller 1831 and a converter circuit. The converter circuitincludes an inductor 1832, a diode 1833 for “freewheeling” of current, acapacitor 1834, and a switch 1835. Driving circuit 1830 is coupled tofiltering output terminals 521 and 522 to receive and then convert afiltered signal into a driving signal for driving an LED moduleconnected between driving output terminals 1521 and 1522.

Switch 1835 has a first terminal coupled to filtering output terminal521, a second terminal coupled to the cathode of freewheeling diode1833, and a control terminal coupled to controller 1831 to receive acontrol signal from controller 1831 for controlling current conductionor cutoff between the first and second terminals of switch 1835. Theanode of freewheeling diode 1833 is connected to filtering outputterminal 522 and driving output terminal 1522. Inductor 1832 has an endconnected to the second terminal of switch 1835, and another endconnected to driving output terminal 1521. Capacitor 1834 is coupledbetween driving output terminals 1521 and 1522, to stabilize the voltagebetween driving output terminals 1521 and 1522.

Controller 1831 is configured for controlling when to turn switch 1835on (in a conducting state) or off (in a cutoff state), according to acurrent detection signal S535 and/or a current detection signal S531.When switch 1835 is switched on, a current of a filtered signal is inputthrough filtering output terminal 521, and then flows through switch1835, inductor 1832, and driving output terminals 1521 and 1522, andthen flows out from filtering output terminal 522. During this flowingof current, the current through inductor 1832 and the voltage ofcapacitor 1834 both increase with time, so inductor 1832 and capacitor1834 are in a state of storing energy. On the other hand, when switch1835 is switched off, inductor 1832 is in a state of releasing energyand thus the current through it decreases with time. In this case, thecurrent through inductor 1832 circulates through driving outputterminals 1521 and 1522, freewheeling diode 1833, and back to inductor1832.

It's worth noting that capacitor 1834 is an optional element, so it canbe omitted and is thus depicted in a dotted line in FIG. 18E. Whencapacitor 1834 is omitted, no matter whether switch 1835 is turned on oroff, the current through inductor 1832 will flow through driving outputterminals 1521 and 1522 to drive the LED module to continue emittinglight.

FIG. 18F is a schematic diagram of an exemplary driving circuitaccording to one embodiment. Referring to FIG. 18F, a driving circuit1930 in this embodiment comprises a buck DC-to-DC converter circuithaving a controller 1931 and a converter circuit. The converter circuitincludes an inductor 1932, a diode 1933 for “freewheeling” of current, acapacitor 1934, and a switch 1935. Driving circuit 1930 is coupled tofiltering output terminals 521 and 522 to receive and then convert afiltered signal into a driving signal for driving an LED moduleconnected between driving output terminals 1521 and 1522.

Inductor 1932 has an end connected to filtering output terminal 521 anddriving output terminal 1522, and another end connected to a first endof switch 1935. Switch 1935 has a second end connected to filteringoutput terminal 522, and a control terminal connected to controller 1931to receive a control signal from controller 1931 for controlling currentconduction or cutoff of switch 1935. Freewheeling diode 1933 has ananode coupled to a node connecting inductor 1932 and switch 1935, and acathode coupled to driving output terminal 1521. Capacitor 1934 iscoupled to driving output terminals 1521 and 1522, to stabilize thedriving of the LED module coupled between driving output terminals 1521and 1522.

Controller 1931 is configured for controlling when to turn switch 1935on (in a conducting state) or off (in a cutoff state), according to acurrent detection signal S531 and/or a current detection signal S535.When switch 1935 is turned on, a current is input through filteringoutput terminal 521, and then flows through inductor 1932 and switch1935, and then flows out from filtering output terminal 522. During thisflowing of current, the current through inductor 1932 increases withtime, so inductor 1932 is in a state of storing energy; but the voltageof capacitor 1934 decreases with time, so capacitor 1934 is in a stateof releasing energy to keep the LED module continuing to emit light. Onthe other hand, when switch 1935 is turned off, inductor 1932 is in astate of releasing energy and its current decreases with time. In thiscase, the current through inductor 1932 circulates through freewheelingdiode 1933, driving output terminals 1521 and 1522, and back to inductor1932. During this circulation, capacitor 1934 is in a state of storingenergy and its voltage increases with time.

It's worth noting that capacitor 1934 is an optional element, so it canbe omitted, as is depicted by the dotted line in FIG. 18F. Whencapacitor 1934 is omitted and switch 1935 is turned on, the currentthrough inductor 1932 doesn't flow through driving output terminals 1521and 1522, thereby making the LED module not emit light. On the otherhand, when switch 1935 is turned off, the current through inductor 1932flows through freewheeling diode 1933 and then the LED module to makethe LED module emit light. Therefore, by controlling the time that theLED module emits light, and the magnitude of current through the LEDmodule, the average luminance of the LED module can be stabilized to beabove a defined value, achieving the effect of emitting a steady light.

FIG. 18G is a block diagram of an exemplary driving circuit according toone embodiment. Referring to FIG. 18G, the driving circuit includes acontroller 2631, and a conversion circuit 2632 for power conversionbased on an adjustable current source, for driving the LED module toemit light. Conversion circuit 2632 includes a switching circuit 2635and an energy storage circuit 2638. And conversion circuit 2632 iscoupled to filtering output terminals 521 and 522 to receive and thenconvert a filtered signal, under the control by controller 2631, into adriving signal at driving output terminals 1521 and 1522 for driving theLED module. Controller 2631 is configured to receive a current detectionsignal S535 and/or a current detection signal S539, for controlling orstabilizing the driving signal output by conversion circuit 2632 to beabove an objective current value. Current detection signal S535represents the magnitude of current through switching circuit 2635.Current detection signal S539 represents the magnitude of currentthrough energy storage circuit 2638, which current may be e.g. aninductor current in energy storage circuit 2638 or a current output atdriving output terminal 1521. Any of current detection signal S535 andcurrent detection signal S539 can represent the magnitude of currentIout provided by the driving circuit from driving output terminals 1521and 1522 to the LED module. Controller 2631 is coupled to filteringoutput terminal 521 for setting the objective current value according tothe voltage Vin at filtering output terminal 521. Therefore, the currentTout provided by the driving circuit or the objective current value canbe adjusted corresponding to the magnitude of the voltage Vin of afiltered signal output by a filtering circuit.

It's worth noting that current detection signals S535 and S539 can begenerated by measuring current through a resistor or induced by aninductor. For example, a current can be measured according to a voltagedrop across a resistor in conversion circuit 2632 the current flowsthrough, or which arises from a mutual induction between an inductor inconversion circuit 2632 and another inductor in its energy storagecircuit 2638.

The above driving circuit structures are especially suitable for anapplication environment in which the external driving circuit for theLED tube lamp includes electronic ballast. An electronic ballast isequivalent to a current source whose output power is not constant. In aninternal driving circuit as shown in each of FIGS. 18C-18F, powerconsumed by the internal driving circuit relates to or depends on thenumber of LEDs in the LED module, and could be regarded as constant.When the output power of the electronic ballast is higher than powerconsumed by the LED module driven by the driving circuit, the outputvoltage of the ballast will increase continually, causing the level ofan AC driving signal received by the power supply module of the LED lampto continually increase, so as to risk damaging the ballast and/orcomponents of the power supply module due to their voltage ratings beingexceeded. On the other hand, when the output power of the electronicballast is lower than power consumed by the LED module driven by thedriving circuit, the output voltage of the ballast and the level of theAC driving signal will decrease continually so that the LED tube lampfail to normally operate.

It's worth noting that the power needed for an LED lamp to work isalready lower than that needed for a fluorescent lamp to work. If aconventional control mechanism of e.g. using a backlight module tocontrol the LED luminance is used with a conventional driving system ofe.g. a ballast, a problem will probably arise of mismatch orincompatibility between the output power of the external driving systemand the power needed by the LED lamp. This problem may even causedamaging of the driving system and/or the LED lamp. To prevent or reducethis problem, using e.g. the power/current adjustment method describedabove in FIG. 18G enables the LED (tube) lamp to be better compatiblewith traditional fluorescent lighting systems.

FIG. 18H is a graph illustrating the relationship between the voltageVin and the objective current value Tout according to an embodiment. InFIG. 18H, the variable Vin is on the horizontal axis, and the variableTout is on the vertical axis. In some cases, when the level of thevoltage Vin of a filtered signal is between the upper voltage limit VHand the lower voltage limit VL, the objective current value Tout will beabout an initial objective current value. The upper voltage limit VH ishigher than the lower voltage limit VL. When the voltage Vin increasesto be higher than the upper voltage limit VH, the objective currentvalue Tout will increase with the increasing of the voltage Vin. Duringthis stage, in certain embodiments, the slope of the relationship curveincreases with the increasing of the voltage Vin. When the voltage Vinof a filtered signal decreases to be below the lower voltage limit VL,the objective current value Tout will decrease with the decreasing ofthe voltage Vin. During this stage, in certain embodiments, the slope ofthe relationship curve decreases with the decreasing of the voltage Vin.For example, during the stage when the voltage Vin is higher than theupper voltage limit VH or lower than the lower voltage limit VL, theobjective current value Tout is in some embodiments a function of thevoltage Vin to the power of 2 or above, in order to make the rate ofincrease/decrease of the consumed power higher than the rate ofincrease/decrease of the output power of the external driving system. Insome embodiments, adjustment of the objective current value Tout is afunction of the filtered voltage Vin to the power of 2 or above.

In another case, when the voltage Vin of a filtered signal is betweenthe upper voltage limit VH and the lower voltage limit VL, the objectivecurrent value Tout of the LED lamp will vary, increase or decrease,linearly with the voltage Vin. During this stage, when the voltage Vinis at the upper voltage limit VH, the objective current value Tout willbe at the upper current limit IH. When the voltage Vin is at the lowervoltage limit VL, the objective current value Tout will be at the lowercurrent limit IL. The upper current limit IH is larger than the lowercurrent limit IL. And when the voltage Vin is between the upper voltagelimit VH and the lower voltage limit VL, the objective current valueTout will be a function of the voltage Vin to the power of 1.

With the designed relationship in FIG. 18H, when the output power of theballast is higher than the power consumed by the LED module driven bythe driving circuit, the voltage Vin will increase with time to exceedthe upper voltage limit VH. When the voltage Vin is higher than theupper voltage limit VH, the rate of increase of the consumed power ofthe LED module is higher than that of the output power of the electronicballast, and the output power and the consumed power will be balanced orequal when the voltage Vin is at a high balance voltage value VH+ andthe current Tout is at a high balance current value IH+. In this case,the high balance voltage value VH+ is larger than the upper voltagelimit VH, and the high balance current value IH+ is larger than theupper current limit IH. On the other hand, when the output power of theballast is lower than the power consumed by the LED module driven by thedriving circuit, the voltage Vin will decrease to be below the lowervoltage limit VL. When the voltage Vin is lower than the lower voltagelimit VL, the rate of decrease of the consumed power of the LED moduleis higher than that of the output power of the electronic ballast, andthe output power and the consumed power will be balanced or equal whenthe voltage Vin is at a low balance voltage value VL− and the objectivecurrent value Tout is at a low balance current value IL−. In this case,the low balance voltage value VL− is smaller than the lower voltagelimit VL, and the low balance current value IL− is smaller than thelower current limit IL.

In some embodiments, the lower voltage limit VL is defined to be around90% of the lowest output power of the electronic ballast, and the uppervoltage limit VH is defined to be around 110% of its highest outputpower. Taking a common AC powerline with a voltage range of 100-277volts and a frequency of 60 Hz as an example, the lower voltage limit VLmay be set at 90 volts (=100*90%), and the upper voltage limit VH may beset at 305 volts (=277*110%).

A short circuit board may be included in at least one of the two endcaps on which to dispose part or all of the power supply. The shortcircuit board may include a first short circuit substrate and a secondshort circuit substrate respectively connected to two terminal portionsof a long circuit sheet disposed in the lamp tube, and electroniccomponents of the power supply module may be respectively disposed onthe first short circuit substrate and the second short circuitsubstrate. The first short circuit substrate and the second shortcircuit substrate may have roughly the same length, or differentlengths. In general, one of the two short circuit substrates has alength that is about 30%-80% of the length of the other short circuitsubstrate. In some embodiments the length of the first short circuitsubstrate is about ⅓ ˜⅔ of the length of the second short circuitsubstrate. For example, in one embodiment, the length of the first shortcircuit substrate may be about half the length of the second shortcircuit substrate. The length of the second short circuit substrate maybe, for example in the range of about 15 mm to about 65 mm, depending onactual application occasions. In certain embodiments, the first shortcircuit substrate is disposed in an end cap at an end of the LED tubelamp, and the second short circuit substrate is disposed in another endcap at the opposite end of the LED tube lamp.

The short circuit board may have a length generally of about 15 mm toabout 40 mm, while the long circuit sheet (e.g., including the flexiblecircuit of the light strip 2) may have a length generally of about 800mm to about 2800 mm. In some embodiments, the short circuit board mayhave a length of about 19 mm to about 36 mm, and the long circuit sheetmay have a length of about 1200 mm to about 2400 mm. In someembodiments, a ratio of the length of the short circuit board to thelength of the long circuit sheet ranges from about 1:20 to about 1:200.

For example, capacitors of the driving circuit, such as capacitors 1634,1734, 1834, and 1934 in FIGS. 18C-18F, in practical use may include twoor more capacitors connected in parallel. Some or all capacitors of thedriving circuit in the power supply module may be arranged on the firstshort circuit substrate of a short circuit board, while other componentssuch as the rectifying circuit, filtering circuit, inductor(s) of thedriving circuit, controller(s), switch(es), diodes, etc. are arranged onthe second short circuit substrate of a short circuit board. Sinceinductors, controllers, switches, etc. are electronic components withhigher temperature, arranging some or all capacitors on a circuitsubstrate separate or away from the circuit substrate(s) ofhigh-temperature components helps prevent the working life of capacitors(especially electrolytic capacitors) from being negatively affected bythe high-temperature components, thereby improving the reliability ofthe capacitors. Further, the physical separation between the capacitorsand both the rectifying circuit and filtering circuit also contributesto reducing the problem of EMI.

In some embodiments, the driving circuit has power conversion efficiencyof 80% or above. In some embodiments, the driving circuit may have apower conversion efficiency of 90% or above (such as, for example, 92%or above). Therefore, without the driving circuit, luminous efficacy ofthe LED lamp may be 120 lm/W or above. In some embodiments, without thedriving circuit, luminous efficacy of the LED lamp may be 160 lm/W orabove. On the other hand, with the driving circuit in combination withthe LED component(s), luminous efficacy of the LED lamp may be 120lm/W*90% (i.e., 108 lm/W) or above. In some embodiments, with thedriving circuit in combination with the LED component(s), luminousefficacy of the LED lamp may be 160 lm/W*92% (i.e., 147.2 lm/W) orabove.

In view of the fact that the diffusion film or layer in an LED tube lamphas light transmittance of 85% or above, luminous efficacy of the LEDtube lamp is in some embodiments 108 lm/W*85%=91.8 lm/W or above, andmay be, in some more effective embodiments, 147.21 m/W*85%=125.121 m/W.

Referring to FIG. 19A, a block diagram of an LED tube lamp including apower supply module in accordance with certain embodiments isillustrated. Compared to the LED lamp shown in FIG. 13D, the LED tubelamp of FIG. 19A comprises two rectifying circuits 510 and 540, afiltering circuit 520, and an LED lighting module 530, and furthercomprises an installation detection module 2520. The installationdetection module 2520 is coupled to the rectifying circuit 510 (and/orthe rectifying circuit 540) via an installation detection terminal 2521and is coupled to the filtering circuit 520 via an installationdetection terminal 2522. The installation detection module 2520 detectsthe signal passing through the installation detection terminals 2521 and2522 and determines whether to cut off an LED driving signal (e.g., anexternal driving signal) passing through the LED tube lamp based on thedetected result. The installation detection module includes circuitryconfigured to perform these steps, and thus may be referred to as aninstallation detection circuit, or more generally as a detection circuitor cut-off circuit. When an LED tube lamp is not yet installed on a lampsocket or holder, or in some cases if it is not installed properly or isonly partly installed (e.g., one side is connected to a lamp socket, butnot the other side yet), the installation detection module 2520 detectsa smaller current and determines the signal is passing through a highimpedance. In this case, in certain embodiments, the installationdetection circuit 2520 is in a cut-off state to make the LED tube lampstop working. Otherwise, the installation detection module 2520determines that the LED tube lamp has already been installed on the lampsocket or holder, and it keeps on conducting to make the LED tube lampworking normally.

For example, in some embodiments, when a current passing through theinstallation detection terminals is greater than or equal to a specific,defined installation current (or a current value), which may indicatethat the current supplied to the lighting module 530 is greater than orequal to a specific, defined operating current, the installationdetection module is conductive to make the LED tube lamp operate in aconductive state. For example, a current greater than or equal to thespecific current value may indicate that the LED tube lamp has correctlyor properly been installed in the lamp socket or holder. When thecurrent passing through the installation detection terminals is smallerthan the specific, defined installation current (or the current value),which may indicate that the current supplied to the lighting module 530is less than a specific, defined operating current, the installationdetection module cuts off current to make the LED tube lamp enter in anon-conducting state based on determining that the LED tube lamp hasbeen not installed in, or does not properly connect to, the lamp socketor holder. In certain embodiments, the installation detection module2520 determines conducting or cutting off based on the impedancedetection to make the LED tube lamp operate in a conducting state orenter non-conducting state. The LED tube lamp operating in a conductingstate may refer to the LED tube lamp including a sufficient currentpassing through the LED module to cause the LED light sources to emitlight. The LED tube lamp operating in a cut-off state may refer to theLED tube lamp including an insufficient current or no current passingthrough the LED module so that the LED light sources do not emit light.Accordingly, the occurrence of electric shock caused by touching theconductive part of the LED tube lamp which is incorrectly installed onthe lamp socket or holder can be better avoided.

Referring to FIG. 19B, a block diagram of an installation detectionmodule in accordance with certain embodiments is illustrated. Theinstallation detection module includes a switch circuit 2580, adetection pulse generating module 2540, a detection result latchingcircuit 2560, and a detection determining circuit 2570. Certain of thesecircuits or modules may be referred to as first, second, third, etc.,circuits as a naming convention to differentiate them from each other.

The detection determining circuit 2570 is coupled to and detects thesignal between the installation detection terminals 2521 (through aswitch circuit coupling terminal 2581 and the switch circuit 2580) and2522. It is also coupled to the detection result latching circuit 2560via a detection result terminal 2571 to transmit the detection resultsignal. The detection determining circuit 2570 may be configured todetect a current passing through terminals 2521 and 2522 (e.g., todetect whether the current is above or below a specific value).

The detection pulse generating module 2540 is coupled to the detectionresult latching circuit 2560 via a pulse signal output terminal 2541,and generates a pulse signal to inform the detection result latchingcircuit 2560 of a time point for latching (storing) the detectionresult. For example, the detection pulse generating module 2540 may be acircuit configured to generate a signal that causes a latching circuit,such as the detection result latching circuit 2560 to enter and remainin a state that corresponds to one of a conducting state or a cut-offstate for the LED tube lamp. The detection result latching circuit 2560stores the detection result according to the detection result signal (ordetection result signal and pulse signal), and transmits or provides thedetection result to the switch circuit 2580 coupled to the detectionresult latching circuit 2560 via a detection result latching terminal2561. The switch circuit 2580 controls the state between conducting orcut off between the installation detection terminals 2521 and 2522according to the detection result.

Referring to FIG. 19C, a block diagram of a detection pulse generatingmodule in accordance with certain embodiments is illustrated. Adetection pulse generating module 2640 may be a circuit that includesmultiple capacitors 2642, 2645, and 2646, multiple resistors 2643, 2647,and 2648, two buffers 2644, and 2651, an inverter 2650, a diode 2649,and an OR gate 2652. With use or operation, the capacitor 2642 and theresistor 2643 connect in series between a driving voltage (e.g., adriving voltage source, which may be a node of a power supply), such asVCC usually defined as a high logic level voltage, and a referencevoltage (or potential), such as ground potential in this embodiment. Theconnection node between the capacitor 2642 and the resistor 2643 iscoupled to an input terminal of the buffer 2644. The resistor 2647 iscoupled between the driving voltage, e.g., VCC, and an input terminal ofthe inverter 2650. The resistor 2648 is coupled between an inputterminal of the buffer 2651 and the reference voltage, e.g. groundpotential in this embodiment. An anode of the diode 2649 is grounded anda cathode thereof is coupled to the input terminal of the buffer 2651.First ends of the capacitors 2645 and 2646 are jointly coupled to anoutput terminal of the buffer 2644, and second, opposite ends of thecapacitors 2645 and 2646 are respectively coupled to the input terminalof the inverter 2650 and the input terminal of the buffer 2651. Anoutput terminal of the inverter 2650 and an output terminal of thebuffer 2651 are coupled to two input terminals of the OR gate 2652.According to certain embodiments, the voltage (or potential) for “highlogic level” and “low logic level” mentioned in this specification areall relative to another voltage (or potential) or a certain referencevoltage (or potential) in circuits, and further may be described as“logic high logic level” and “logic low logic level.”

When an end cap of an LED tube lamp is inserted into a lamp socket andthe other end cap thereof is electrically coupled to a human body, orwhen both end caps of the LED tube lamp are inserted into the lampsocket, the LED tube lamp is conductive with electricity. At thismoment, the installation detection module enters a detection stage. Thevoltage on the connection node of the capacitor 2642 and the resistor2643 is high initially (equals to the driving voltage, VCC) anddecreases with time to zero finally. The input terminal of the buffer2644 is coupled to the connection node of the capacitor 2642 and theresistor 2643, so the buffer 2644 outputs a high logic level signal atthe beginning and changes to output a low logic level signal when thevoltage on the connection node of the capacitor 2642 and the resistor2643 decreases to a low logic trigger logic level. As a result, thebuffer 2644 is configured to produce an input pulse signal and thenremain in a low logic level thereafter (stops outputting the input pulsesignal.) The width for the input pulse signal may be described as equalto one (initial setting) time period, which is determined by thecapacitance value of the capacitor 2642 and the resistance value of theresistor 2643.

Next, the operations for the buffer 2644 to produce the pulse signalwith the initial setting time period will be described below. Since thevoltage on a first end of the capacitor 2645 and on a first end of theresistor 2647 is equal to the driving voltage VCC, the voltage on theconnection node of both of them is also a high logic level. The firstend of the resistor 2648 is grounded and the first end of the capacitor2646 receives the pulse signal from the buffer 2644, so the connectionnode of the capacitor 2646 and the resistor 2648 has a high logic levelvoltage at the beginning but this voltage decreases with time to zero(in the meantime, the capacitor stores the voltage being equal to orapproaching the driving voltage VCC.) Accordingly, initially theinverter 2650 outputs a low logic level signal and the buffer 2651outputs a high logic level signal, and hence the OR gate 2652 outputs ahigh logic level signal (a first pulse signal) at the pulse signaloutput terminal 2541. At this moment, the detection result latchingcircuit 2560 stores the detection result for the first time according tothe detection result signal and the pulse signal. During that initialpulse time period, detection pulse generating module 2540 outputs a highlogic level signal, which results in the detection result latchingcircuit 2560 outputting the result of that high logic level signal.

When the voltage on the connection node of the capacitor 2646 and theresistor 2648 decreases to the low logic trigger logic level, the buffer2651 changes to output a low logic level signal to make the OR gate 2652output a low logic level signal at the pulse signal output terminal 2541(stops outputting the first pulse signal.) The width of the first pulsesignal output from the OR gate 2652 is determined by the capacitancevalue of the capacitor 2646 and the resistance value of the resistor2648.

The operation after the buffer 2644 stops outputting the pulse signal isdescribed as below. For example, the operation may be initially in anoperating stage. Since the capacitor 2646 stores the voltage beingalmost equal to the driving voltage VCC, and when the buffer 2644instantaneously changes its output from a high logic level signal to alow logic level signal, the voltage on the connection node of thecapacitor 2646 and the resistor 2648 is below zero but will be pulled upto zero by the diode 2649 rapidly charging the capacitor. Therefore, thebuffer 2651 still outputs a low logic level signal.

On the other hand, when the buffer 2644 instantaneously changes itsoutput from a high logic level signal to a low logic level signal, thevoltage on the one end of the capacitor 2645 also changes from thedriving voltage VCC to zero instantly. This makes the connection node ofthe capacitor 2645 and the resistor 2647 have a low logic level signal.At this moment, the output of the inverter 2650 changes to a high logiclevel signal to make the OR gate output a high logic level signal (asecond pulse signal.) The detection result latching circuit 2560 storesthe detection result for a second time according to the detection resultsignal and the pulse signal. Next, the driving voltage VCC charges thecapacitor 2645 through the resistor 2647 to make the voltage on theconnection node of the capacitor 2645 and the resistor 2647 increasewith time to the driving voltage VCC. When the voltage on the connectionnode of the capacitor 2645 and the resistor 2647 increases to reach ahigh logic trigger logic level, the inverter 2650 outputs a low logiclevel signal again to make the OR gate 2652 stop outputting the secondpulse signal. The width of the second pulse signal is determined by thecapacitance value of the capacitor 2645 and the resistance value of theresistor 2647.

As those mentioned above, in certain embodiments, the detection pulsegenerating module 2640 generates two high logic level pulse signals inthe detection stage, which are the first pulse signal and the secondpulse signal. These pulse signals are output from the pulse signaloutput terminal 2541. Moreover, there is an interval with a defined timebetween the first and second pulse signals (e.g., an opposite-logicsignal, which may have a low logic level when the pulse signals have ahigh logic level), and the defined time is determined by the capacitancevalue of the capacitor 2642 and the resistance value of the resistor2643).

From the detection stage entering the operating stage, the detectionpulse generating module 2640 does not produce the pulse signal any more,and keeps the pulse signal output terminal 2541 on a low logic levelpotential. As described herein, the operating stage is the stagefollowing the detection stage (e.g., following the time after the secondpulse signal ends). The operating stage occurs when the LED tube lamp isat least partly connected to a power source, such as provided in a lampsocket. For example, the operating stage may occur when part of the LEDtube lamp, such as only one side of the LED tube lamp, is properlyconnected to one side of a lamp socket, and part of the LED tube lamp iseither connected to a high impedance, such as a person, and/or isimproperly connected to the other side of the lamp socket (e.g., ismisaligned so that the metal contacts in the socket do not contact metalcontacts in the LED tube lamp). The operating stage may also occur whenthe entire LED tube lamp is properly connected to the lamp socket.

Referring to FIG. 19D, a detection determining circuit in accordancewith certain embodiments is illustrated. An exemplary detectiondetermining circuit 2670 includes a comparator 2671, and a resistor2672. A negative input terminal of the comparator 2671 receives areference logic level signal (or a reference voltage) Vref, a positiveinput terminal thereof is grounded through the resistor 2672 and is alsocoupled to a switch circuit coupling terminal 2581. Referring to FIGS.19B and 19D, the signal flowing into the switch circuit 2580 from theinstallation detection terminal 2521 outputs to the switch circuitcoupling terminal 2581 to the resistor 2672. When the current of thesignal passing through the resistor 2672 reaches a certain level (forexample, bigger than or equal to a defined current for installation,(e.g. 2A) and this makes the voltage on the resistor 2672 higher thanthe reference voltage Vref (referring to two end caps inserted into thelamp socket) the comparator 2671 produces a high logic level detectionresult signal and outputs it to the detection result terminal 2571. Forexample, when an LED tube lamp is correctly installed on a lamp socket,the comparator 2671 outputs a high logic level detection result signalat the detection result terminal 2571, whereas the comparator 2671generates a low logic level detection result signal and outputs it tothe detection result terminal 2571 when a current passing through theresistor 2672 is insufficient to make the voltage on the resistor 2672higher than the reference voltage Vref (referring to only one end capinserted into the lamp socket.) Therefore, in some embodiments, when theLED tube lamp is incorrectly installed on the lamp socket or one end capthereof is inserted into the lamp socket but the other one is groundedby an object such as a human body, the current will be too small to makethe comparator 2671 output a high logic level detection result signal tothe detection result terminal 2571.

Referring to FIG. 19E, a schematic detection result latching circuitaccording to some embodiments of the present invention is illustrated. Adetection result latching circuit 2660 includes a D flip-flop 2661, aresistor 2662, and an OR gate 2663. The D flip-flop 2661 has a CLK inputterminal coupled to a detection result terminal 2571, and a D inputterminal coupled to a driving voltage VCC. When the detection resultterminal 2571 first outputs a low logic level detection result signal,the D flip-flop 2661 initially outputs a low logic level signal at a Qoutput terminal thereof, but the D flip-flop 2661 outputs a high logiclevel signal at the Q output terminal thereof when the detection resultterminal 2571 outputs a high logic level detection result signal. Theresistor 2662 is coupled between the Q output terminal of the Dflip-flop 2661 and a reference voltage, such as ground potential. Whenthe OR gate 2663 receives the first or second pulse signals from thepulse signal output terminal 2541 or receives a high logic level signalfrom the Q output terminal of the D flip-flop 2661, the OR gate 2663outputs a high logic level detection result latching signal at adetection result latching terminal 2561. The detection pulse generatingmodule 2640 only in the detection stage outputs the first and the secondpulse signals to make the OR gate 2663 output the high logic leveldetection result latching signal, and thus the D flip-flop 2661 decidesthe detection result latching signal to be the high logic level or thelow logic level the rest of the time, e.g. including the operating stageafter the detection stage. Accordingly, when the detection resultterminal 2571 has no high logic level detection result signal, the Dflip-flop 2661 keeps a low logic level signal at the Q output terminalto make the detection result latching terminal 2561 also keep a lowlogic level detection result latching signal in the detection stage. Onthe contrary, once the detection result terminal 2571 has a high logiclevel detection result signal, the D flip-flop 2661 outputs and keeps ahigh logic level signal (e.g., based on VCC) at the Q output terminal.In this way, the detection result latching terminal 2561 keeps a highlogic level detection result latching signal in the operating stage aswell.

Referring to FIG. 19F, a schematic switch circuit according to someembodiments is illustrated. A switch circuit 2680 includes a transistor,such as a bipolar junction transistor (BJT) 2681, as being a powertransistor, which has the ability of dealing with high current/power andis suitable for the switch circuit. The BJT 2681 has a collector coupledto an installation detection terminal 2521, a base coupled to adetection result latching terminal 2561, and an emitter coupled to aswitch circuit coupling terminal 2581. When the detection pulsegenerating module 2640 produces the first and second pulse signals, theBJT 2681 is in a transient conduction state. This allows the detectiondetermining circuit 2670 to perform the detection for determining thedetection result latching signal to be a high logic level or a low logiclevel. When the detection result latching circuit 2660 outputs a highlogic level detection result latching signal at the detection resultlatching terminal 2561, the BJT 2681 is in the conducting state to makethe installation detection terminals 2521 and 2522 conducting. Incontrast, when the detection result latching circuit 2660 outputs a lowlogic level detection result latching signal at the detection resultlatching terminal 2561 and the output from detection pulse generatingmodule 2640 is a low logic level, the BJT 2681 is cut-off or in theblocking state to make the installation detection terminals 2521 and2522 cut-off or blocking.

Since the external driving signal is an AC signal and in order to avoidthe detection error resulting from the logic level of the externaldriving signal being just around zero when the detection determiningcircuit 2670 detects, the detection pulse generating module 2640generates the first and second pulse signals to let the detectiondetermining circuit 2670 perform two detections. So the issue of thelogic level of the external driving signal being just around zero in asingle detection can be avoided. In some cases, the time differencebetween the productions of the first and second pulse signals is notmultiple times of half one cycle of the external driving signal. Forexample, it does not correspond to the multiple phase differences of 180degrees of the external driving signal. In this way, when one of thefirst and second pulse signals is generated and unfortunately theexternal driving signal is around zero, it can be avoided that theexternal driving signal is again around zero when the other pulse signalis generated.

The time difference between the productions of the first and secondpulse signals, for example, an interval with a defined time between bothof them can be represented as following:

-   -   the interval=(X+Y)(T/2),    -   where T represents the cycle of an external driving signal, X is        a natural number, 0<Y<1, with Y in some embodiments in the range        of 0.05-0.95, and in some embodiments in the range of 0.15-0.85.

Furthermore, in order to avoid the installation detection moduleentering the detection stage from misjudgment resulting from the logiclevel of the driving voltage VCC being too small, the first pulse signalcan be set to be produced when the driving voltage VCC reaches or ishigher than a defined logic level. For example, in some embodiments, thedetection determining circuit 2670 works after the driving voltage VCCreaching a high enough logic level in order to prevent the installationdetection module from misjudgment due to an insufficient logic level.

According to the examples mentioned above, when one end cap of an LEDtube lamp is inserted into a lamp socket and the other one floats orelectrically couples to a human body or other grounded object, thedetection determining circuit outputs a low logic level detection resultsignal because of high impedance. The detection result latching circuitstores the low logic level detection result signal based on the pulsesignal of the detection pulse generating module, making it as the lowlogic level detection result latching signal, and keeps the detectionresult in the operating stage, without changing the logic value. In thisway, the switch circuit keeps cutting-off or blocking instead ofconducting continually. And further, the electric shock situation can beprevented and the requirement of safety standard can also be met. On theother hand, when two end caps of the LED tube lamp are correctlyinserted into the lamp socket, the detection determining circuit outputsa high logic level detection result signal because the impedance of thecircuit for the LED tube lamp itself is small. The detection resultlatching circuit stores the high logic level detection result signalbased on the pulse signal of the detection pulse generating module,making it as the high logic level detection result latching signal, andkeeps the detection result in the operating stage. So the switch circuitkeeps conducting to make the LED tube lamp work normally in theoperating stage.

In some embodiments, when one end cap of the LED tube lamp is insertedinto the lamp socket and the other one floats or electrically couples toa human body, the detection determining circuit outputs a low logiclevel detection result signal to the detection result latching circuit,and then the detection pulse generating module outputs a low logic levelsignal to the detection result latching circuit to make the detectionresult latching circuit output a low logic level detection resultlatching signal to make the switch circuit cutting-off or blocking. Assuch, the switch circuit blocking makes the installation detectionterminals, e.g. the first and second installation detection terminals,blocking. As a result, the LED tube lamp is in non-conducting orblocking state.

However, in some embodiments, when two end caps of the LED tube lamp arecorrectly inserted into the lamp socket, the detection determiningcircuit outputs a high logic level detection result signal to thedetection result latching circuit to make the detection result latchingcircuit output a high logic level detection result latching signal tomake the switch circuit conducting. As such, the switch circuitconducting makes the installation detection terminals, e.g. the firstand second installation detection terminals, conducting. As a result,the LED tube lamp operates in a conducting state.

Thus, according to the operation of the installation detection module, afirst circuit, upon connection of at least one end of the LED tube lampto a lamp socket, generates and outputs two pulses, each having a pulsewidth, with a time period between the pulses. The first circuit mayinclude various of the elements described above configured to output thepulses to a base of a transistor (e.g., a BJT transistor) that serves asa switch. The pulses occur during a detection stage for detectingwhether the LED tube lamp is properly connected to a lamp socket. Thetiming of the pulses may be controlled based on the timing of variousparts of the first circuit changing from high to low logic levels, orvice versa.

The pulses can be timed such that, during that detection stage time, ifthe LED tube lamp is properly connected to the lamp socket (e.g., bothends of the LED tube lamp are correctly connected to conductiveterminals of the lamp socket), at least one of the pulse signals occurswhen an AC current from a driving signal is at a non-zero level. Forexample, the pulse signals can occur at intervals that are differentfrom half of the period of the AC signal. For example, respective startpoints or mid points of the pulse signals, or a time between an end ofthe first pulse signal and a beginning of the second pulse signal may beseparated by an amount of time that is different from half of the periodof the AC signal (e.g., it may be between 0.05 and 0.95 percent of amultiple of half of the period of the AC signal). During a pulse thatoccurs when the AC signal is at a non-zero level, a switch that receivesthe AC signal at the non-zero level may be turned on, causing a latchcircuit to change states such that the switch remains permanently on solong as the LED tube lamp remains properly connected to the lamp socket.For example, the switch may be configured to turn on when each pulse isoutput from the first circuit. The latch circuit may be configured tochange state only when the switch is on and the current output from theswitch is above a threshold value, which may indicate a properconnection to a light socket. As a result, the LED tube lamp operates ina conducting state.

On the other hand, if both pulses occur when a driving signal at the LEDtube lamp has a near-zero current level, or a current level below aparticular threshold, then the state of the latch circuit is notchanged, and so the switch is only on during the two pulses, but thenremains permanently off after the pulses and after the detection mode isover. For example, the latch circuit can be configured to remain in itspresent state if the current output from the switch is below thethreshold value. In this manner, the LED tube lamp remains in anon-conducting state, which prevents electric shock, even though part ofthe LED tube lamp is connected to an electrical power source.

It is worth noting that according to certain embodiments, the width ofthe pulse signal generated by the detection pulse generating module isbetween 10 μs to 1 ms, and it is used to make the switch circuitconducting for a short period when the LED tube lamp conductsinstantaneously. In some embodiments, a pulse current is generated topass through the detection determining circuit for detecting anddetermining. Since the pulse is for a short time and not for a longtime, the electric shock situation will not occur. Furthermore, thedetection result latching circuit also keeps the detection result duringthe operating stage (e.g., the operating stage being the period afterthe detection stage and during which part of the LED tube lamp is stillconnected to a power source), and no longer changes the detection resultstored previously complying with the circuit state changing. A situationresulting from changing the detection result can thus be avoided. Insome embodiments, the installation detection module, such as the switchcircuit, the detection pulse generating module, the detection resultlatching circuit, and the detection determining circuit, could beintegrated into a chip and then embedded in circuits for saving thecircuit cost and layout space.

In embodiments of the present invention, a safety switch (which may bealternatively called a protective switch) is configured in the end capfor preventing leakage current and can connect the conductive pin 301 tothe power supply module. For example, in connection with the previousfigures, such a safety switch may be located between one of pins 501,502, 503, or 504 (see FIGS. 13A-13D, for example), which may be externalpins, and a part of a power supply module, such as a rectifier 510 or540 of a power supply module. When the LED tube lamp iscorrectly/properly installed into or connected to a lamp socket orholder, the safety switch is triggered (e.g., the power supply module iselectrically connected to the conductive pin 301). In this way, the endcap does not conduct electricity before the LED tube lamp is correctlyinstalled into the lamp socket. And this provides the safety protectionto the user for preventing the user from electric shock in case that oneend of the LED tube lamp is inserted into the lamp socket but the otherend is touched by the user's hand. In some embodiments, the safetyswitch is a (liquid) level switch triggered only through the LED tubelamp being correctly installed. And when the level switch is triggered(so that liquid flows to a preset position, for example, when moved byan actuator), the LED tube lamp works normally. A micro switch may betriggered by an actuator when the electrically conductive pin is pluggedinto the socket and the actuator is pressed. The end cap is configuredto, likewise, turn on the micro switch and, directly or through a relay,close the circuit only when the electrically conductive pin is pluggedinto the socket.

In some embodiments, two safety switches are configured into tworespective end caps on both ends of the LED tube lamp. Or, in otherembodiments, only one safety switch is configured into one end cap, inwhich case, the end cap configured with the safety switch may be markedfor reminding the user of first installing the unmarked end cap.

Referring to FIG. 20, a schematic structure of an LED tube lampaccording to some embodiments of the present invention is illustrated.The LED tube lamp 100 may include one or more of the features describedin the various above embodiments. The LED tube lamp 100 includes a lamptube 1 and two end caps 3 (the proportion of the end caps 3 in relationto the lamp tube 1 schematized in FIG. 20 is exaggerated in order tohighlight the structure of the end cap 3. In certain embodiments, thedepth of each end cap 3 (e.g., length along a longitudinal direction ofthe lamp tube 1) is from 9 to 70 mm, and the axial length (e.g., alongthe longitudinal direction) of the lamp tube 1 is from 254 to 2000 mm,e.g., from 10 inchs to 80 inches.) The end caps 3 are respectivelyconfigured at the both ends of the lamp tube 1. In one embodiment eachend cap 3 includes an electrically conductive pin 301. In addition, oneor both end caps may include an actuator 332, a micro switch 334, andall of part of a power supply module (e.g., a power supply module suchas described previously). The end caps 3 may each include some or all ofthese components and in some embodiments do not include any additionalcomponents other than these components. When the LED tube lamp 100 iscorrectly/properly installed into a lamp socket or holder (not shown),the actuator 332 triggers the micro switch 334 for allowing the powersupply module to electrically connect to externally input (commercial)electricity so as to light up the LED components (e.g., LED sources orLEDs as described in previous figures) in the LED tube lamp 100.

In accordance with an exemplary embodiment, the end cap 3 includes ahousing, an electrically conductive pin 301, a power supply 5 and asafety switch. The safety switch is positioned between the electricallyconductive pin 301 and the power supply 5. The end cap may be configuredto contain the safety switch when the end cap is attached to an end ofthe lamp tube (e.g., by including a flange or other device that preventsthe safety switch from moving outside the lamp tube). The safety switchmay further include a micro switch 334 and an actuator 332. The end caps3 are disposed on two ends of the glass tube 1 and are configured toturn on the safety switch—and make a circuit connecting, sequentially,main electricity coming from a socket of a lamp holder, the electricallyconductive pin 301, the power supply 5 and the LED light assembly—whenthe electrically conductive pin 301 is plugged into the socket. The endcap 3 is configured to turn off the safety switch and open the circuitwhen the electrically conductive pin 301 is unplugged from the socket ofthe lamp holder. The lamp tube 1 is thus configured to minimize risk ofelectric shocks during installation and to comply with safetyregulations.

In some embodiments, the safety switch directly—andmechanically—completes and breaks the circuit of the LED tube lamp. Forexample, an actuator can be used that moves when the lamp is properlyplugged in, and as a result pushes a switch such as a micro-switch tocause the switch to electrically close, and therefore conductelectricity between components connected to one end of the switch andcomponents connected to the other end of the switch. In otherembodiments, the safety switch controls another electrical circuit, i.e.a relay, which in turn completes and breaks the circuit of the LED tubelamp. Some relays use an electromagnet to operate a switching mechanismmechanically, but other operating principles are also used. For example,solid-state relays control power circuits with no moving parts, insteadusing a semiconductor device to perform switching.

Various safety switches, may be used for preventing an electric shock ona person who has improperly or incompletely installs the LED tube lampinto a lamp holder. These safety switches may include the micro switch334 mentioned above. Examples of these safety switches, includingvarious examples of actuators connected to a micro switch, can be seenin U.S. patent application Ser. No. 15/066,645, filed Mar. 10, 2016, andincorporated herein in its entirety by reference.

As shown in FIG. 21, an input terminal 3341 and an output terminal 3343are respectively electrically connected to a hollow conductive pin (notshown) and a power supply module (not shown), correspondingly. Thoughnot shown, an actuator, such as described above in connection with FIG.20 and/or in U.S. patent application Ser. No. 15/066,645 may be includedthat, when moved, causes the micro switch 334 to be in a closed-circuitposition. A bidirectional triode thyristor (TRIAC) 3345 is configuredbetween the input terminal 3341 and the output terminal 3343, a resistor3347 embodying a current-limiting device or component is electricallycoupled to an a1 end of the micro switch 334, which has an a2 endelectrically coupled to a trigger/control terminal of the TRIAC 3345. Inone embodiment, the resistance of the resistor 3347 is from 1 Ohm to 10KOhm, and in some cases, about 2K Ohm. In some embodiments, the currentpassing through the micro switch 334 in FIG. 21 is as small as about 0.1A, compared to about 10 A, which is the value of the current passingthrough the embodiment of the micro switch 334 in FIG. 20. Accordingly,a micro switch 334 can be selected from a wider range of devices capableof tolerating the smaller current, and selecting from a wider range isconducive to reducing cost of the micro switch 334.

The safety switch could include a silicon controlled rectifier (SCR) asthe current-limiting device in place of the resistor 3347; i.e., thesafety switch may include the SCR, the TRIAC 3345, and the micro switch334, wherein the micro switch 334 could comprise any micro switch in theembodiments mentioned above. The current-limiting device may be referredto herein as a current-limiting circuit. In one embodiment, the inputterminal 3341 of the safety switch is electrically connected to anyhollow conductive pin (e.g., external connection pin) of the LED tubelamp, and the output terminal 3343 thereof is electrically connected tothe power supply module. Ends of the TRIAC 3345 are electrically coupledto the input terminal 3341 and the output terminal 3343, respectively.Further, the SCR is electrically coupled to the micro switch 334 inseries. One end of the serially connected SCR and the micro switch 334is electrically coupled to the control terminal of the TRIAC 3345, theother end of the serially connected SCR and the micro switch 334 iselectrically coupled to the input terminal 3341.

When the micro switch 334 switches to an open-circuit position, thecontrol terminal of the TRIAC 3345 is not coupled to the input terminal3341. Meanwhile, the TRIAC 3345 is in a cutoff state so as to make thehollow conductive pin uncoupled to the power supply module. When themicro switch 334 is triggered/actuated and shorted (e.g., when itchanges to a closed-circuit position), the current is transmitted fromthe input terminal 3341, the serially connected SCR and the micro switch334 to the control terminal of the TRIAC 3345 to trigger the TRIAC 3345,causing it to conduct. Therefore, the hollow conductive pin 301 iscoupled to the power supply module to make the LED tube lamp operatenormally.

In the abovementioned embodiments with the safety switch by using themicro switch 334 only, an enormous instantaneous or transient current,for example bigger than 10 A, is an inrush flowing through the microswitch 334, the power supply module, and the LED components when themicro switch 334 is instantly triggered. Therefore, not only is themicro switch 334 likely to stand or endure a higher instantaneouscurrent, but the volume thereof also is bigger. Further, theinstantaneous current may damage the power supply module and the LEDcomponents. However, in some embodiments, the instantaneous currentcould be limited or restrained by the SCR or the resistor 3347 so as tolower the maximum current the micro switch 334 has to be able towithstand or endure, and simultaneously, the volume of the micro switch334 and the cost can both be reduced. In this way, the current passingthrough the micro switch could be as low as about 0.1 A.

The LED tube lamps according to various different embodiments aredescribed as above. With respect to an entire LED tube lamp, thefeatures mentioned herein and in the embodiments may be applied inpractice singly or integrally such that one or more of the mentionedfeatures is practiced or simultaneously practiced.

According to certain embodiments of the power supply module, theexternal driving signal may be low frequency AC signal (e.g., commercialpower), high frequency AC signal (e.g., that provided by a ballast), ora DC signal (e.g., that provided by a battery), input into the LED tubelamp through a drive architecture of single-end power supply or dual-endpower supply. For the drive architecture of dual-end power supply, theexternal driving signal may be input by using only one end thereof assingle-end power supply.

The LED tube lamp may omit the rectifying circuit when the externaldriving signal is a DC signal.

According to certain embodiments of the rectifying circuit in the powersupply module, there may be a single rectifying circuit, or dualrectifying circuit. First and second rectifying circuits of the dualrectifying circuit are respectively coupled to the two end caps disposedon two ends of the LED tube lamp. The single rectifying circuit isapplicable to the drive architecture of signal-end power supply, and thedual rectifying circuit is applicable to the drive architecture ofdual-end power supply. Furthermore, the LED tube lamp having at leastone rectifying circuit is applicable to the drive architecture of lowfrequency AC signal, high frequency AC signal or DC signal.

The single rectifying circuit may be a half-wave rectifier circuit orfull-wave bridge rectifying circuit. The dual rectifying circuit maycomprise two half-wave rectifier circuits, two full-wave bridgerectifying circuits or one half-wave rectifier circuit and one full-wavebridge rectifying circuit.

According to certain embodiments of the pin in the power supply module,there may be two pins in a single end (the other end has no pin), twopins in corresponding end of two ends, or four pins in corresponding endof two ends. The designs of two pins in single end two pins incorresponding end of two ends are applicable to signal rectifyingcircuit design of the of the rectifying circuit. The design of four pinsin corresponding end of two ends is applicable to dual rectifyingcircuit design of the of the rectifying circuit, and the externaldriving signal can be received by two pins in only one end or in twoends. And the pins may alternatively be called input terminals.

According to certain embodiments of the filtering circuit of the powersupply module, there may be a single capacitor, or n filter circuit. Thefiltering circuit filers the high frequency component of the rectifiedsignal for providing a DC signal with a low ripple voltage as thefiltered signal. The filtering circuit also further comprises the LCfiltering circuit having a high impedance for a specific frequency forconforming to current limitations in specific frequencies of the ULstandard. Moreover, the filtering circuit according to some embodimentsfurther comprises a filtering unit coupled between a rectifying circuitand the pin(s) for reducing the EMI.

According to certain embodiments of the LED lighting module, the LEDlighting module may comprise the LED module and the driving circuit, oronly the LED module. The LED module may be connected with a voltagestabilization circuit for preventing the LED module from overvoltage.The voltage stabilization circuit may be a voltage clamping circuit,such as zener diode, DIAC and so on. When the rectifying circuit has acapacitive circuit, in some embodiments, two capacitors are respectivelycoupled between corresponding two pins in two end caps and so the twocapacitors and the capacitive circuit as a voltage stabilization circuitperform a capacitive voltage divider.

In some embodiments, if there are the LED module and the driving circuitin the LED lighting module, the driving circuit may be a buck converter,a boost converter, or a buck-boost converter. The driving circuitstabilizes the current of the LED module at a defined current value, andthe defined current value may be modulated based on the external drivingsignal. For example, the defined current value may be increased with theincreasing of the level of the external driving signal and reduced withthe reducing of the level of the external driving signal. Moreover, amode switching circuit may be added between the LED module and thedriving circuit for switching the current from the filtering circuitdirectly or through the driving circuit inputting into the LED module.

According to certain embodiments of the LED module of the power supplymodule, the LED module comprises plural strings of LEDs connected inparallel with each other, wherein each LED may have a single LED chip orplural LED chips emitting different spectrums. Each LEDs in differentLED strings may be connected with each other to form a mesh connection.

Having described at least one of the embodiments with reference to theaccompanying drawings, it will be apparent to those skills in the artthat the disclosure is not limited to those precise embodiments, andthat various modifications and variations can be made in the presentlydisclosed system without departing from the scope or spirit of thedisclosure. It is intended that the present disclosure covermodifications and variations of this disclosure provided they comewithin the scope of the appended claims and their equivalents.Specifically, one or more limitations recited throughout thespecification can be combined in any level of details to the extent theyare described to improve the LED tube lamp. These limitations include,but are not limited to, a shock-preventing safety switch.

Though certain documents are described as being incorporated byreference herein, and the subject matter of those applications has beenincorporated by reference herein, the following claims should beinterpreted according to claim construction in view of the terminologyand language used in this application. In addition, while variousaspects of the inventive concept have been described with reference toexemplary embodiments, it will be apparent to those skilled in the artthat various changes and modifications may be made without departingfrom the spirit and scope of the inventive concept. Therefore, it shouldbe understood that the disclosed embodiments are not limiting, butillustrative.

What is claimed is:
 1. A light emitting diode (LED) tube lamp,comprising: a lamp tube, having a first pin and a second pin forreceiving an external driving signal; an LED module configured foremitting light; a power supply module, configured for supplying powerfrom the external driving signal to the LED module; a micro switchcoupled to the power supply module; and an actuator configured to causethe micro switch to change to a closed-circuit position to allow thepower supply module to supply power to the LED module for emittinglight; wherein the LED tube lamp is configured such that when the LEDtube lamp is properly installed into a lamp holder, the micro switchcloses to electrically connect the power supply module to an externaldriving signal.
 2. The LED tube lamp according to claim 1, comprising anend cap having the first pin and the second pin and attached to theactuator, the end cap including the micro switch.
 3. The LED tube lampaccording to claim 1, wherein the power supply module includes a firstrectifying circuit coupled to the first pin and the second pin andconfigured to rectify the external driving signal to produce a rectifiedsignal; and includes a filtering circuit coupled to the first rectifyingcircuit and configured to filter the rectified signal to produce afiltered signal
 4. The LED tube lamp according to claim 3, wherein theLED module is part of an LED lighting module coupled to the filteringcircuit and configured to receive the filtered signal for emittinglight.
 5. The LED tube lamp according to claim 1, wherein the LED tubelamp is configured such that when the LED tube lamp is not properlyinstalled into a lamp holder and the external driving signal is receivedby the lamp tube, the actuator doesn't cause the micro switch to changeto the closed-circuit position, so that the power supply module doesn'tsupply power to the LED lighting module.
 6. The LED tube lamp accordingto claim 1, comprising two of the actuator and two of the micro switch,the two actuators for triggering/actuating the two micro switches to theclosed-circuit position and respectively coupled to two ends of the lamptube; and the two micro switches coupled to the power supply module. 7.The LED tube lamp according to claim 1, wherein the micro switchcomprises a liquid level switch.
 8. The LED tube lamp according to claim1, further comprising: a thrysistor and a current-limiting device,wherein the thyristor is coupled between the first pin and a first endof the micro switch, and the current-limiting device is coupled betweenthe first pin and a second end of the micro switch.
 9. A light emittingdiode (LED) tube lamp, comprising: a lamp tube, having a first pin and asecond pin for receiving an external driving signal; an LED lightingmodule configured for emitting light; a power supply module, configuredfor supplying power from the external driving signal to the LED lightingmodule; a safety switch having an input terminal and an output terminal,and comprising a thyristor, a current-limiting device, and a microswitch, the input terminal coupled to one of the first pin and thesecond pin, and the output terminal coupled to the power supply module,wherein the thyristor is coupled between the input terminal and theoutput terminal, the current-limiting device is coupled between theinput terminal and a first end of the micro switch, and a second end ofthe micro switch is coupled to a control terminal of the thyristor; andan actuator configured to cause the micro switch to change to aclosed-circuit position to allow the power supply module to supply powerto the LED lighting module for emitting light; wherein the LED tube lampis configured such that when the LED tube lamp is properly installedinto a lamp holder, the output terminal of the safety switch is coupledto the power supply module, and the external driving signal is received,the actuator causes the micro switch to change to the closed-circuitposition to make the thyristor conduct current, which conductingthyristor allows the power supply module to supply power to the LEDlighting module for emitting light.
 10. The LED tube lamp according toclaim 9, comprising an end cap having the first pin and attached to theactuator, the end cap configured to contain the safety switch when theend cap is attached to an end of the lamp tube.
 11. The LED tube lampaccording to claim 9, wherein the power supply module includes a firstrectifying circuit coupled to the first pin and the second pin andconfigured to rectify the external driving signal to produce a rectifiedsignal; and includes a filtering circuit coupled to the first rectifyingcircuit and configured to filter the rectified signal to produce afiltered signal.
 12. The LED tube lamp according to claim 11, whereinthe LED lighting module is coupled to the filtering circuit andconfigured to receive the filtered signal for emitting light.
 13. TheLED tube lamp according to claim 9, wherein the LED tube lamp isconfigured such that when the LED tube lamp is not properly installedinto a lamp holder and the external driving signal is received by thelamp tube, the actuator doesn't cause the micro switch to change to theclosed-circuit position, so that the power supply module doesn't supplypower to the LED lighting module.
 14. The LED tube lamp according toclaim 9, comprising two of the actuator and two of the safety switch,the two actuators for respectively triggering/actuating two of the microswitches respectively of the two safety switches to the closed-circuitposition to electrically conduct current between respectively coupled totwo ends of the lamp tube and the power supply module.
 15. The LED tubelamp according to claim 9, wherein the micro switch comprises a liquidlevel switch.
 16. The LED tube lamp according to claim 9, wherein thethyristor comprises a bidirectional triode thyristor.
 17. The LED tubelamp according to claim 9, wherein the current-limiting device comprisesa resistor or a silicon controlled rectifier.
 18. The LED tube lampaccording to claim 17, wherein the resistance of the resistor is in arange between about 1 k ohms and about 10 k ohms.
 19. The LED tube lampaccording to claim 9, wherein the LED tube lamp is configured such thatwhen the micro switch is actuated by the actuator to the closed-circuitposition, the current-limiting device limits an instantaneous currentthrough the micro switch to about 0.1 A or less.